Firm 10 oz 283g for crystal clear bubble free castings this is more powerful than the composimold original 100 reusable mould making material that works well by melting pouring this mould is a flexible rubbery thermoplastic that is great for small mould parts that require a stiffer mould making material compatible with many different casting materials including clays plaster cement expoxy polyurethane and many others other sizes available sold separately 20 oz 567g cmpm20 40 o