Our best selling tool uses inexpensive razor blades and makes perfect lap joints in any plastic film covering. We machine this from solid aluminum bar stock. The film travels in one of the eight slots - which give you eight places to dull the blade. Turn the blade over and you have eight more. Imagine how jealous your friends will be when they find out you trimmed an entire model perfectly with only one inexpensive razor blade.Harry HigleyPart HIGJFT001