Actually thinking about it the short ones of mine came from Mike, the longer 40” ones came from fleabay .The ones Asha illustrated appear to be the same as the ones I use, which came from Mike Walker

Bursting out of the side would indicate that perhaps you are pushing too hard.Mine either burst out of the side of the cable (the metal coaxial sheathed type), or the plastic sleeve comes away from the button end, usually because it splits. I don't know what I do to them really!
I've got at least three or four others somewhere but I can't find them. I think they're hiding in fear for their lives.![]()
Yes I agree about flexibility.The ony problem I've come across recently with a modern cable release like the illustrated release is that they can be a bit too inflexible I tried to fit one to my Rolleicord recently and it interfered with the Rollei QRP and I couldn't use it. Otherwise I've been quite happy with the newish releases I have bought. I keep a release in the camera case with each camera system generally so I can just pick up the case, grab some film and a tripod and I'm good to go.
If there is one thing I've learned in recent years is that most modern cable releases are utter rubbish and as for the ones with the thick plastic outer sheath I think one is better off poking the shutter button with a stick! Vintage ones really are the way to go but sadly very few come on to the market.I've got a few vintage cable releases, I figure if the thing still works after 40 years chances are it'll keep on going.
Current favourite is a Bronica branded one from the 70's.
I've broke dozens of the cheap ebay ones