Prescott Plastics 1 1/4 Inch Round Plastic Plug, Pipe Tubing End Cap, Durable Chair Glide 1.25" (1 1/4") Black PP.1.250.RBP

What is the plug length? (the part that fits inside the tube)

Do these fit standard US 1 1/4" steel pipe ? (the pipe's OD is actually 1.66" and ID is 1.38")

I need caps for a hard 1" inside diameter and hard 1.25" outside diameter, will these work?

Would these fit into 3/4 sch 40 irrigation pvc ? It's ok if I have to really jam them to get them in, the outside finished diameter is fine..