Product Description Two acrylic plates are connected at the top with a hinge and separated by two 1 3/4 inch screws at the bottom of the device. The back plate has a hole for putting the tackle through. Wing-nuts are used on the screws to bring the plates closer together. You can tighten the crusher all the way, making the open space only 1 inch wide. The front plate is clear acrylic, and the back plate with the tackle hole is dark-tint acrylic. Both acrylic plates are 5 inch across and 7 inch long. Switch between SLOW or FAST to control the frequency of the shock, or adjust the dial to control the strength of the shock. Manufacturer Contact Information 85 portmanmoor