GUKO ADAPTER: Silicone | Multi-size adjustable | ‘UniStop’

Description

Guko Adapter ‘UNI-STOP’.

This is an innovative product designed to replace all similar adapters. Each one is made using premium and heavy duty silicone to ensure lasting usability and best performance.

Reverse grip-ribs for maximum seal
Universal, fits multiple neck sizes
​Internal barb seal, for ease of neck insert

Price is for one.
For alternative Silicon Stopper option, click here

Wikipedia info