German field telephone wire spools were designed to fit on backpack dispensers. They were made for the Wehrmacht by a variety of companies. Each spool could hold approximately 1 km of single conductor field telephone wire.
For reenacting, I use modern two-conductor US military surplus field telephone wire. It comes on 0.5 km spools. I wind it on to the German spools using a WW2 German backpack fitted with a crank and chain.
Check out my new book on WW2 German field telephone equipment…https://www.lulu.com/en/us/shop/rotwang-manteuffel/world-war-2-german-field-telephone-equipment-a-basic-guide-for-reenactors-and-historians/paperback/product-976w9q.html?page=1&pageSize=4
WW2 German Field Telephone Equipment 