SMALL SS316 “FILTER BOX” containers are built as standard with body and head in AISI 316 and have a CLAMP type closure. The “FILTER BOX” SMALL OT58 containers are built as standard with the body in AISI 304, the head in nickel-plated OT58, and have a locking ring. Both SMALL “FILTER BOX” containers can be bracketed and are equipped on the head with connections for pressure gauges and air vent and have a 1/4 “connection on the container as standard for water purging.