I'm planning to replace soldered/sweat shutoff valves (which are stuck and not working) with push fittings. Already done under bath sink with the help of heat gun.
I noticed something attached to the copper supply lines (feeding cold water to the faucet) with orange tube hanging (behind shutoff valves). I want to know what is that? Please see pictures [.
And is it safe to use heat gun/unsolder the shutoff valve with that thing behind?