Lastolite LL LB7554 Knitted Curtain Background Arizona 3 x 3. 5m Description. The new range of curtain backgrounds come in six popular colours & are made from a knitted fabric which can be draped or stretched to instantly remove any creases. Fully machine washable at 40C 105F in a large washing machine these backgrounds are available in two sizes 3m x 3. 5m & 3m x 7m. Each background is supplied in a handy tote bag & features a hem on the 3m edge to insert a pole for support. A set of 4 clips are also included to secure the background when stretched between the stands of a support system as shown below.