Good clamp - does what's needed,
This review is from: Silverline 868498 Quick Clamp Heavy Duty 600mm (Tools & Hardware)
I've used this clamp for a couple of jobs now and it's been great. It slides easily and grips well. The clamp ends are also fairly good and can handle the pressure applied, unlike a couple I've come across in the past that seem to just break.
My only draw back regarding my purchase was that I had it on my wish list and someone bought at £14 I think, which seems a little pricey, though obviously the prices vary a fair amount on Amazon. Still a good quality product though.