The Westlab ‘UNI-STOP’ stopper is an innovative product designed by Westlab to replace all of your stoppers. Each stopper has the ability to transform from a solid stopper to a stopper with one hole for a range of experiments.Reverse grip-ribs for maximum seal.Two in one, solid or one hole.Universal, fits multiple neck sizes.Internal barb seal, for ease of tubing insert.Universal hole, fits tubing from 6-10mm D.A truly innovative product, unique to Westlab.