This fish trap is made of heavily galvanized wire. The traps are 16" (42 cm) long x 9" (23 cm) wide at largest diameter and have a 7/8" (22 mm) diameter entrance hole. The MT2 1/4" (6.4 mm) square mesh traps minnow size fish and the MT28 1/8" (3.2 mm) square mesh is for smaller fish. Info from AES