1、The small square box and the large square box are assembled with jacks, which is easy to operate and use. 2、Mainly used to install in the air inlet of an oil-free air compressor to effectively reduce noise during work. 3、The threaded mounting hole is accurate, the size is standard, and it has a good stability. 4、The two square boxes are small and compact for easy installation and disassembly. 5、The muffler is mainly used in dental air filters and oil-free air compressors, and has strong practicability. Item Type: Filter Silencer Large Square Box Size: Approx. 161 x 56 x 65mm / 6.3 x 2.2 x 2.6in (height does not include hole height) Small Square Box Size: Approx. 48 x 48 x 55mm / 1.9 x 1.9 x 2.2in (height does not include hole height) Threaded Hole Installation Center Distance: Approx. 76mm / 3in Purpose: Dental air filter silencer, oil-free air compressor; How to Use: Assemble the small square box with the large square box through the socket. 1 x Large Square Box 1 x Small Square Box