Create the ultimate strength building workout with Bowflex Select Tech 10-90 lb Dumbbell. Two 1090 dumbbells (each sold separately) replaces up to 34 individual dumbbells. With just the turn of a dial, you can automatically change your resistance from 10 lbs all the way to 90 lbs, in 5 lb increments.Create the ultimate strength building workout with Bowflex Select Tech 10-90 lb Dumbbell. Two 1090 dumbbells (each sold separately) replaces up to 34 individual dumbbells. With just the turn of a dial, you can automatically change your resistance from 10 lbs all the way to 90 lbs, in 5 lb increments.