Topog-E molded rubber boiler gaskets are rated to 180lbs. and 380 degrees F. These inspection plate gaskets are used on steam boilers, water and air tanks. Made in various shapes and sizes the most common shapes being elliptical and obround. The sizes are measured by laying the gasket flat and measuring the inside width x the inside height. The third dimension is the flange width. Installation: Do not use any lubricant, grease or adhesive, make sure both mating surfaces are clean, dry, and as smooth as possible, tighen nut enough to give a snug fit, then give a 1/4 turn with a wrench.