Characteristics and performance

The Hallite 777 double-acting, energised piston seal is a compact seal for medium to heavy-duty applications designed to fit a range of industry standard grooves making it ideal for retrofitting existing products.

Comprised of a tough, wear-resistant thermoplastic polyurethane face seal pre-loaded with a square or rectangular cross-section NBR energizer depending on the groove proportions. The square or rectangular energiser provides an equal load on the seal face while also providing improved stability over a conventional O-ring energiser. This design allows this seal to be used in smaller grooves without compromising the performance of the sealing system.

Product details

The standard face material for the Hallite 777 is Hythane® 743, one of Hallite’s high temperature polyurethanes (HTPU). Additional material options are available. The energiser material comes in a number of material options to extend operating conditions. Contact your local Hallite technical team to decide which is best for your application.

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Temp range


Max speed


* Max pressure stated is dependant on the material variant selected. Please consult the datasheet for further information.