The Rungne Maglock Primer is a chalk blend that solves a specific problem: chalk that clumps, flakes off, or disappears on the crux. The formula combines silica silylate, magnesium carbonate, and amino acids to work together as a system, with the silica prepping the skin surface so the magnesium carbonate holds through long boulder problems or multi-pitch days where reapplication breaks focus. What Our Gearhead(R) Experts Are Saying:"I use this as a base layer before chalking up. The ultra-fine silica silylate fills in the micro-texture of the skin so the magnesium carbonate actually has something to grip onto."