Stretchy white bags that fit over the skimmer to attract oils, lotions and cosmetics in the water and trap debris too fine for the skimmer basket to catch. Has small weights in the corners to help hold the bag in the skimmer basket. Ideal for pools that get alot of pine needles, we use them on our pool to trap dog hair! Bags stretch to fit a maximum of a 24cm skimmer basket. 1 bag supplied.