These adjustable dumbbells have weights that adjust from 10 to 90 lbs in 5 lb. increments. Easy-to-use selection dials for adjusting weights. Replaces up to 17 pairs of dumbbells. They are sold as a pair. Great for toning and strength training exercises for both upper and lower body including heavy leg lifts. Compatible with the free Bowflex SelectTech® training App for iOS and Android..