This swab is made of soft and absorbent cloth and sized specifically for the boot joint. It is intended to be introduced into the large bore and pulled out of the small bore. The beaded chain weight enables it to pass around the u-tube.
This swab is intended to succeed where old fashioned push swabs fail. The bottom of the boot joint near the u-tube is the wettest area of the bassoon. It is essential that moisture in this area be removed. Push swabs are unable to service this area adequately, leaving moisture in the area which can potentially cause the wood to rot. This pull swab succeeds in removing the moisture in these areas, including from the u-tube itself.
This swab is not intended to be used in the wing joint. It is too large to pass through the small end of that joint and it will get stuck.