--- title: Donaldson Hy-Pro Lube & Hydraulic Filtration Industry Blog | compressor description: compressor | Learn about hydraulic fluid, lube oil, diesel fuel and industrial fluid contamination, filtration and conditioning on the Donaldson Hy-Pro blog. --- [![Donaldson Hy-Pro Logo_White](https://www.hyprofiltration.com/hs-fs/hubfs/Hy-Pro%20Logos/Donaldson%20Hy-Pro%20Logo_White.png?width=591&height=265&name=Donaldson%20Hy-Pro%20Logo_White.png) ![Donaldson Hy-Pro Logo 2](https://www.hyprofiltration.com/hs-fs/hubfs/Hy-Pro%20Logos/Donaldson%20Hy-Pro%20Logo%202.png?width=584&height=262&name=Donaldson%20Hy-Pro%20Logo%202.png) ](https://www.hyprofiltration.com) [**](https://www.hyprofiltration.com/blog/topic/compressor#tmpmodule_1568675152246189) [![Distributors](https://no-cache.hubspot.com/cta/default/170326/6a993b6f-f737-4a22-8a35-a45c4da5c3b4.png)](https://cta-redirect.hubspot.com/cta/redirect/170326/6a993b6f-f737-4a22-8a35-a45c4da5c3b4) ![ECATALOG](https://no-cache.hubspot.com/cta/default/170326/interactive-162302555948.png) ** ###### 1 min read ### [Hy-Pro's Product Spotlight: Compact Offline Filter (COF)](https://www.hyprofiltration.com/blog/productspotlight-cof) By [Hy-Pro Marketing](https://www.hyprofiltration.com/blog/author/hy-pro-marketing) on Thu, Apr. 01, 2021 # Hy-Pro's Compact Offline Filter Our newest and smallest unit yet, the Compact Offline Filter is able[![COF_Group-2](https://www.hyprofiltration.com/hs-fs/hubfs/COF_Group-2.jpg?width=201&name=COF_Group-2.jpg)](https://www.hyprofiltration.com/products/fluid-conditioning-equipment/offline-filter-system/cof-overview-0) to fit where no other filtration equipment can. Ideal for smaller systems or where a larger offline system wouldn't fit, this solution can be permanently installed or made portable for ease of use.  ###### Topics: [hydraulic fluid](https://www.hyprofiltration.com/blog/topic/hydraulic-fluid) [contamination](https://www.hyprofiltration.com/blog/topic/contamination) [dirt](https://www.hyprofiltration.com/blog/topic/dirt) [Water Contamination](https://www.hyprofiltration.com/blog/topic/water-contamination) [hydraulic filters](https://www.hyprofiltration.com/blog/topic/hydraulic-filters) [hydraulic and lubrication filter types](https://www.hyprofiltration.com/blog/topic/hydraulic-and-lubrication-filter-types) [Gearbox filtration](https://www.hyprofiltration.com/blog/topic/gearbox-filtration) [new oil](https://www.hyprofiltration.com/blog/topic/new-oil) [micro-dieseling](https://www.hyprofiltration.com/blog/topic/micro-dieseling) [fluid samples](https://www.hyprofiltration.com/blog/topic/fluid-samples) [filtration](https://www.hyprofiltration.com/blog/topic/filtration) [oil analysis](https://www.hyprofiltration.com/blog/topic/oil-analysis) [hydraulic pump](https://www.hyprofiltration.com/blog/topic/hydraulic-pump) [filters](https://www.hyprofiltration.com/blog/topic/filters) [hydraulic valve](https://www.hyprofiltration.com/blog/topic/hydraulic-valve) [FSL](https://www.hyprofiltration.com/blog/topic/fsl) [liquid conditioning station](https://www.hyprofiltration.com/blog/topic/liquid-conditioning-station) [duplex low-pressure](https://www.hyprofiltration.com/blog/topic/duplex-low-pressure) [oxidation](https://www.hyprofiltration.com/blog/topic/oxidation) [Noria](https://www.hyprofiltration.com/blog/topic/noria) [NSD](https://www.hyprofiltration.com/blog/topic/nsd) [hydraulic](https://www.hyprofiltration.com/blog/topic/hydraulic) [cellulose media](https://www.hyprofiltration.com/blog/topic/cellulose-media) [compressor](https://www.hyprofiltration.com/blog/topic/compressor) [Reliable Plant](https://www.hyprofiltration.com/blog/topic/reliable-plant) [filter comparison](https://www.hyprofiltration.com/blog/topic/filter-comparison) [lube oil](https://www.hyprofiltration.com/blog/topic/lube-oil) [aluminum refinery](https://www.hyprofiltration.com/blog/topic/aluminum-refinery) [conditioning](https://www.hyprofiltration.com/blog/topic/conditioning) [turbine oil](https://www.hyprofiltration.com/blog/topic/turbine-oil) [glass media](https://www.hyprofiltration.com/blog/topic/glass-media) ###### 3 min read ### [Understanding ISO Codes](https://www.hyprofiltration.com/blog/understanding-iso-codes) By [Hy-Pro Marketing](https://www.hyprofiltration.com/blog/author/hy-pro-marketing) on Thu, Feb. 25, 2021 # ISO Cleanliness Codes Explained The ISO Cleanliness Code (per ISO4406-1999) is used to quantify particulate contamination levels per milliliter of fluid at 3 sizes - 4µ, 6µ, and 14µ. It is expressed in 3 numbers (example 19/17/14) where each number represents a contaminant level code for the correlating particle size. The code includes all particles of the specified size and larger. For a detailed breakdown and a handy ISO code cheat sheet, see our [ISO Code Guide & Cheat Sheet](https://www.hyprofiltration.com/blog/iso-4406-cleanliness-codes)![Example of an ISO cleanliness code showing particle counts in hydraulic fluid at 4, 6, and 14 micron sizes.](https://www.hyprofiltration.com/hs-fs/hubfs/Screen%20Shot%202021-02-23%20at%202.50.37%20PM.png?width=283&name=Screen%20Shot%202021-02-23%20at%202.50.37%20PM.png)It is important to note that each time a code increases, the quantity range of particles is doubling. Inversely, as a code decreases by one the contaminant level is cut in half.  ###### Topics: [hydraulic fluid](https://www.hyprofiltration.com/blog/topic/hydraulic-fluid) [dirt](https://www.hyprofiltration.com/blog/topic/dirt) [hydraulic filters](https://www.hyprofiltration.com/blog/topic/hydraulic-filters) [Gearbox filtration](https://www.hyprofiltration.com/blog/topic/gearbox-filtration) [vacuum dehydration](https://www.hyprofiltration.com/blog/topic/vacuum-dehydration) [filter housing sizing](https://www.hyprofiltration.com/blog/topic/filter-housing-sizing) [plastic injection molding manufacturer](https://www.hyprofiltration.com/blog/topic/plastic-injection-molding-manufacturer) [oil darkening](https://www.hyprofiltration.com/blog/topic/oil-darkening) [mining](https://www.hyprofiltration.com/blog/topic/mining) [fluid samples](https://www.hyprofiltration.com/blog/topic/fluid-samples) [total systems cleanliness](https://www.hyprofiltration.com/blog/topic/total-systems-cleanliness) [metal analysis](https://www.hyprofiltration.com/blog/topic/metal-analysis) [filter performance](https://www.hyprofiltration.com/blog/topic/filter-performance) [paper mill](https://www.hyprofiltration.com/blog/topic/paper-mill) [fluid transfer](https://www.hyprofiltration.com/blog/topic/fluid-transfer) [filters](https://www.hyprofiltration.com/blog/topic/filters) [hydraulic valve](https://www.hyprofiltration.com/blog/topic/hydraulic-valve) [coalesce technology](https://www.hyprofiltration.com/blog/topic/coalesce-technology) [filter cart](https://www.hyprofiltration.com/blog/topic/filter-cart) [cleanliness](https://www.hyprofiltration.com/blog/topic/cleanliness) [COD](https://www.hyprofiltration.com/blog/topic/cod) [hydraulic oil](https://www.hyprofiltration.com/blog/topic/hydraulic-oil) [gearbox](https://www.hyprofiltration.com/blog/topic/gearbox) [duplex high-pressure](https://www.hyprofiltration.com/blog/topic/duplex-high-pressure) [compressor](https://www.hyprofiltration.com/blog/topic/compressor) [filter elements](https://www.hyprofiltration.com/blog/topic/filter-elements) [lube oil](https://www.hyprofiltration.com/blog/topic/lube-oil) [turbine oil](https://www.hyprofiltration.com/blog/topic/turbine-oil) [desiccant](https://www.hyprofiltration.com/blog/topic/desiccant) [demulsibility](https://www.hyprofiltration.com/blog/topic/demulsibility) [All posts](https://www.hyprofiltration.com/blog/all) ### Featured ### Sign up for updates ## Have a Question for Donaldson Hy-Pro? 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