This product is manufactured in the UK to the highest standards, and is 400mm wide, 7mu in thickness and 600 metres in length. 36 x Rolls of Clear Pre-Stretch Ext Core Pallet Stretch Shrink Wrap, 400mm x 7mu x 600M Rolls. Pre-Stretch is becoming increasingly popular in the UK. It is pallet wrap that has been pre-stretched, to meet its optimum length. The thickness of pre-stretch is always 7mu, but this is already stretched hence is broadly equivalent to a 17mu roll before its stretched. The benefit of pre-stretch is the 600 metres length, which you know you are getting out of the roll - whereas standard hand pallet wrap relies on the packer 'stretching' the wrap to its full capacity.