The new Solas Concord YJ-CD-12/17 blows away the performance of your stock impeller! Large blade area and superior hub design deliver increased acceleration and top speed.YJ-CD-12/17 is designed for modified Yamaha SuperJet & EX applications with TR-1 engine. The YJ-CD-12/17 Solas Concord Impeller is featured in our Yamaha 2021 SuperJet Stage 1 and EX Stage 1 Performance Kits.