An MEKP (Methyl Ethyl Ketone Peroxide) Accelerated Catalyst. Also Known as Hardener, or just Peroxide.
We recommend this product only because it is pure and consistent. Use between 1.5% and 3% in your polyester resins. See the advice on cans for the optimum quantity.
Overcatalysing resin causes a rubbery, soft resin. Undercatalysed resin will not go hard.