Anti-static wrist strap:

These devices are worn to prevent static discharge while working on static sensitive equipment.  Anti-static wrist straps work by continuously discharging static electricity as it is generated.  These wrist straps that have a grounding cord attached are a must for anyone who works inside a computer. 

Cordless wrist straps:

These wrist straps must be worn for at least 15 minutes before performing computer repair.  It's stainless steal back must touch bare skin.  Some technicians prefer this device, because it's cordless and allows them freedom to move about without unclipping a grounding cord.

Ant-Static Spray:

These sprays remove dust and dirt as well as prevent static build-up on plastic and metal surfaces.