Fukiya (Blowgun) Arrow protection tubes. Handmade: Paper product 10 pieces, various designs 2 sets The length of the protection tubes is the same for each set. Please refer to the photo of the arrows inserted for length. The recommended point is Length! Commercially available products are made of plastic and are short, so you tend to push the arrows in, which widens the mouth of the arrow. (The mouth also widens due to the weight during storage even without pushing.) Effective in preventing this. I had a failure during a match where the mouth of the arrow was widened and it got stuck, causing the arrow to fly off in a completely unexpected direction.