I find most shops appreciate the supply of biscuits/choc bars-loosens a lot of parts. While back was jumping in on the counter at local bike shop,lad walks in for 700C long valve tube,duly handed over £6.95, we asked if he’d like us to fit it for a fiver. He said he could do it himself, paid and did one. Re-appears about 15 of your earth minutes later saying the tube is faulty,ok..? we cough up another tube (Specialized),same as his “FAULTY”,ahem… one apologise about first one and he leaves. 10 minutes later (Pattern here..),he’s back this one is faulty too…,what are the chances?,ask him if he has used lever to refit tube, he replies no.We say Werry Sowwy. “Bring your wheel in and we will fit tube for you”, gratis as it’s getting expesive,all this, for shop. He brings in wheel shallow rim, I fit long valve tube,as it was what he wanted,tyres were very tight… . He goes out happy, we examine tubes and they have little slits in them like they have been nipped by some kind of a lever you might use to remove a tyre,what do they call them?,thats it! Tyre levers!!. Anyhoo, thanks to what the French might call this bouton de porte,I scored two Spesh tubes, which I still have patched up!! 🙂