The Whirl-Pak Sponge Probe is designed for surface sampling and is effective for hard-to-reach areas. The sponge is adhered to a holder that is screwed onto a handle (both pieces are made of polypropylene). The probe is sterilized with ethylene oxide gas inside a 24-oz. (710 ml) write-on bag. To use, add buffer to the bag, squeeze out the excess, swab the surface, insert the sponge back into the bag and, while holding it from the outside, unscrew the handle and discard. Then drop the sponge into the bag, close, and send to a lab for testing. The probe measures 8" (20.3 cm) long. Box of 50.