u/NorthStatistician

So , I just found an old king tempo for like 50 bucks and the place to put the ring seem not connected to slide . However , the little knob seem to help sliding. Should I slide it using my thumb or theres an other way around ?

Edit for futur lurker : The answer is simple , some old trumpet dont have one. The knob i was speakimg is not the place for a lyre( hole where you can put a screw) but the small one on the side of slide but my english is trugling this morning lol .