Please Use the updated version by bodgeitquick at http://www.thingiverse.com/thing:14879 This is a copy of the size template found in UK post offices. It lets you find what category your item falls into, as postage is not weight and size dependant in the UK.This is provided without any warranty, don't have a go at me if you get charged for not using enough postage. (I've had them check items in the post office with their size guide and still be charged for not applying the correct postage!)Laser cut, the holes are designed for a 0.5mm beam.