USCP utilizes a rubber gasket on all of our round structures.  The gasket and joint are designed to meet the requirements of ASTM C443 in order to provide a long term watertight joint.  The profile shape of our joint is designed as the same profile used by standard concrete manholes.  This allows our joint to match standard precast manhole joints around the country.  Should the need ever arise to interchange a USCP manhole component with a regular concrete component, it is likely they pieces will fit.  The design of our ASTM C443 joint is required to meet a design pressure of 13 psi without the use of joint sealant or external joint wrap.  Our joints were never intended to be used with an external joint wrap to provide the required watertightness.  Should added insurance be desired for deep installations or very wet conditions, our recommendation would be to use a high quality butyl rope joint sealant.