Keystone 400 W HPS Magnetic Ballast – 4-Tap Input

Designed for 1 × 400 W high-pressure sodium (HPS / S51) lamp operation

4-tap input: 120 / 208 / 240 / 277 V for installation versatility

High power factor (HPF) design for better electrical efficiency

Magnetic construction ensures durability and compatibility in traditional HPS systems

Compact dimensions (~4.3" × 4.14" × 4.8") make it suitable for many fixture types

Covered by Keystone’s 2-year warranty for reliable support