Model No. C-500 thru C-582: 6-pieces per bag. Model No. C-600 thru C-680: 4-pieces per bag. Model No. C-690 thru C-792: 2-pieces per bag. Model No. C-818 thru C-858: 2-pieces per bag. All other compression springs are 1-piece per bag. The Century Spring C-510 1/2" Compression Springs 6 Pack is a premium assortment of compression springs designed to deliver outstanding performance in a wide range of applications. Manufactured from high-quality steel, these compression springs exhibit excellent strength, durability, and resistance to wear and tear, making them reliable for long-term use. At the core of the Century Spring C-510 compression springs is precise engineering that ensures consistent and optimal compression resistance. This key feature allows the springs to withstand varying degrees of pressure while maintaining their original form and functionality. These compression springs have a 1/2" diameter, making them suitable for diverse projects that require compression force management.