what is this fitting called??

[desertwater]

Ive never seen a coupling such as that one that goes from cts to ips It must be something old school. Maybe they invented copper before sweating? Maybe they hadn't invented sweatable gate valve/ball valve yet? Hope I don't sound dumb :/

 

[speedbump]

Dresser couplings were like PVC compression couplings. A metal flange on both ends with rubber between the flange's and the tube. When you tighten the long bolts that hold the whole unit together, it squeezes the rubber around the pipes to be joined. Apparently the rubber could squeeze enough to seal on copper or galvanized.