Duraplast UK™ 15mm Superseal Tube Support Pushfit Pipe Insert Pack of 50 | Dual O-Rings for Extra Sealing Security | for Plastic Pushfit Pipe and Fittings | Fast Dispatch : Amazon.co.uk: DIY
JG Speedfit White Plastic Push-fit Pipe insert, Pack of 50
John Guest Speedfit Pipe Insert 15mm (Pack Of 10) | eBay