The Hillman Group`s No. 15 fastener PACK is a reliable choice for all your industrial and scientific needs. These screws have ample strength and durability to hold up against heavy duty applications. The pack contains enough screws to last through multiple projects without having to refill your supply. The only downside is that the screws can be difficult to remove if you make a mistake during installation. Overall a great product for professionals working in the industrial and scientific fields..