The cable is 3/8 galv aircraft cable. I used J hooks into the trees .A 12” turnbuckle and three ubolts at each end of the cable. The weakest link in the system is rated at just under 700lb....the cable is rated at over 10,000lb......it’s all pretty steady.
The most important thing about this is that the kids absolutely love it and it brings back memories of camp Iona at Herbert for me!!