Membrane housing 4040 Model  L  L1 D A B WTM4021-1 605 545 φ102 1/2" 3/4" 1/2" WTM4040-1  1084 1024 φ102 1/2" 3/4" 1/2" WTM4040-2  2100 2040 φ102 3/4" 1/2" WTM4040-3  3119 2056 φ102 3/4" 1/2" WTM4040-4  4132 4072 φ102 3/4" 1/2"