MSM (Methylsulfonylmethane) supports healthy joint function and flexibility for your horse. Select the Best only uses 100 percent pure MSM to ensure the highest quality and maximum MSM support for your horse.1 lbs. - 46-day administration for one horse2 lbs. - 92-day administration for one horse4 lbs. - 184-day administration for one horse | Select the Best MSM Powder Equine Supplement | Size 2 lb