The player keeps the bag inflated by blowing air into it through a blowpipe or pumping air into it with a bellows. Materials used for bags vary widely, but the most common are the skins of local animals such as goats, dogs, sheep, and cows. More recently, bags made of synthetic materials includingGore-Tex have become much more common. Though a drawback of the synthetic bag is the potential for fungal spores to colonise the bag because of reduction in necessary cleaning, with the associated danger of lung infection.
Bags cut from larger materials are usually saddle-stitched with an extra strip folded over the seam and stitched (for skin bags) or glued (for synthetic bags) to reduce leaks. Holes are then cut to accommodate the stocks. In the case of bags made from largely intact animal skins the stocks are typically tied into the points where limbs and the head joined the body of the living animal, a construction technique common in Central and Eastern Europe.
