I recently tackled a pinball playfield rotisserie project and these clamps are the perfect compliment. Easier to use than standard C clamps and the plastic non-marring surface makes it a little safer on the playfield surface. You can find more info about the clamps at the Irwin website. The $2 (each) discount is provided via rebate and you can only have 3 items per rebate, per household. So, I bought two pairs and will use the sales receipts and rebate forms with two different addresses. If you like these, don’t wait, last day of the sale is June 28.