Up for sale is 5 pieces of a -345 AS568 size BROWN FKM o-rings with 75 Durometer hardness.Viton®/FKM has excellent resistance to chemicals, acidsand fuel as well as high temperature. It should not be used in applications of steam or hot water. The temperature range for this material is 5 to 400 F. Color is no indication of material or hardness it is typcially used to distinguish it from other black materials. Shipping via USPS First Class is included in the price.NOMINAL SIZEINSIDE DIAMETEROUTSIDE DIAMETERCROSS SECTION 4" 4-3/8" 3/16"Our BROWN FKM O-rings meet or exceed the following ASTM D2000 Standard: ASTM D2000 M6HK810, A1-10, B38, EF31, EO88, F15, Z1:75Check our feedback and buy with confidence! We sell quality seals and gaskets and we back up everything we sell 100%.Payment for this item is by Paypal or Credit Card. Please contact us with any questions BEFORE buying. Download our o-ring size chart here: AS568 SizesViton is a registered trademark of DuPont Performance Elastomers.Powered by eCRATER . List your items fast and easy and manage your active items. jetgasket Store On Sep-07-09 at 17:56:39 PDT, seller added the following information:1st Class USPS Postage includes a label and a tracking number. We never ship anything with just a stamp!