Slime Self Healing TubeSlime Self Healing Tube come supplied pre-filled with Slime.SlimeSlime has been recognised as the number one name in bicycle inner tube sealants since its introduction in 1989.'Self healing' means if you get a puncture, Slime fibres plug the hole before the tube suffers significant air loss. This means you can usually carry on riding without having to stop to patch and/or inflate the tube.'Slime Tube sealant prevents and repairs flat tires caused by puncturing objects up to 1/8? (3mm) in diameter. Microfibers in our patented formula are carried by the escaping air to the puncture where they build up to form a plug that prevents air loss. Slime works repeatedly to repair new and existing punctures and is guaranteed to perform for up to 2 years!'Slime.The Slime Self Healing Tube is pre filled with Slime.A Slime 700x19/25 Self Healing Tube weighs 183g.(For reference, a standard 700 x 20/28 Specialized inner tubeweighs 100g.)Be aware that cycling equipment specifications can change without notice so please regard our published weights as an honest but approximate guide.