When purchasing a square bracket, assume the brackets are 90 degrees. Not this one. I am very disappointed, the clamp itself is strong but useless for the job. I was trying to glue 2 boards together and when I applied some pressure the boards started falling apart. I checked for squareness and the horizontal arm was about 1/32 off, which is a lot since the arm is only about 1 inch tall. Would never buy this again.