These work great for toys where you only need a little bit of pressure to hold the parts in place. There are better small clamps out there, but you can get these for 99 cents each with a coupon. With the lifetime warranty, it's hard to beat that price.
One problem I encountered was the clamps slipping. For years I have waxed the bars on my clamps to prevent the glue from sticking to them. If I put wax on these clamps, they slip. I quick wipe down with some mineral spirits took care of it. If your clamps slip, clean the bar.