1971-72 Topps Trio set. According to the SCD article (link below) these were inserts in regular 1971-72 Topps basketball wax packs. I picked up the full set at the National a few years ago for $100 which I thought was kind of steep. I visited the dealer a few times and he wouldn't budge on the price. Finally the last day of the show I hadn't spent all my money and the set was still sitting in his binder so I forked over the cash. Glad I did now.
https://www.sportscollectorsdaily.co...in-high-grade/