The Straitline Crayons Black x 2 are professional marking crayons designed for challenging work surfaces where standard markers fail. These waterproof, non-toxic crayons deliver reliable marking performance on oily, slick, wet, cold or dry surfaces, making them essential for site work in all weather conditions. Ideal for use across multiple trade applications, these black marking crayons work effectively on timber, concrete, ceramics and metal surfaces. Their versatile formulation ensures consistent marking whether you're working with construction materials, fabrication projects or outdoor installations where moisture and surface contamination are common challenges. Supplied as a convenient card of 2 crayons, this pack provides reliable marking tools for professional tradespeople who need dependable performance across varied site conditions. Features and Benefits:Waterproof formulation maintains marking visibility in wet conditionsNon-toxic composition ensures safe use in enclose