MAGNETIC - Five rubber surrounded magnets attach to any ferrous surface. Cable Tie Sizes Supplied (100 of each size): 100 x 2.5mm, 160 x 4.5mm, 250 x 4.5mm, 300 x 4.5mm and 380 x 4.5mm. Overall size (without cable ties W x D x H): 115 x 70 x 270mm.
eBay