MTM Hydro's O-Rings will fit in any 1/4", 3/8", and 1/2" coupler in the U.S. Market. We, alone, sell well over 100,000 O-rings per year as this item is commonly (and accidentally) blown out at the worst of times. From amateurs to contract cleaners, everybody blows out O-rings, the difference is that the Pro's always have a few spare O-Rings in the truck.
As a Wholesaler, we receive these by the thousands and offer them in 25 and 100 packs only.
Dont get caught without a few extra O-Rings on the job as these little items make a big difference in maintaining PSI, GPM, and safety.
Types of O-Rings:
Buna Nitril is a common and inexpensive compound used in the O-Rings of all MTM Hydro Brass Couplers. This compound will perform acceptably at high temperatures but will deteriorate quickly and should only be used in cold water applications.
FKM (Fluro-Elastomer) is a more expensive and durable compound meant for Hot Water and performs well with Chemical applications. Use the FKM Series of O-rings for replacement on Stainless Steel Fittings.
EDPM is more expensive and durable compound that performs well with Hot water but excellently with Chemical Applications. All MTM Hydro Stainless Steel Couplers have EDPM O-Rings, although we do not sell replacements; instead, replace with FKM.