Retail price $15.00, rental price $15.00. Methyl-Sulfonyl-Methane (MSM) is a naturally occurring substance known for its diverse health benefits, including support for healthy nails. It is known to boost the production of keratin, a tough protein from which finger and toe nails are made. MSM paired with Shield Plasticizers make nails much stronger and more flexible. Shield Plasticizers keep nails flexible, shiny and more resistant to shock and abrasion. Chip-free for days!