I purchased 4 of these magnets. They measure about 3 1/2 by 4 3/4 inches. They have good magnetic force to hold 1/4" x 2" x 5" and 3/8" x 2" x 6" steel weld samples. The magnets hold coupons easily and are likely to hold larger coupons. I will probably buy larger magnets for assembly projects from this manufacturer in the future. The magnets are well colored, don't corrode and appear to be well made. I recommend them.