The Difference between 1000 Watt Double

https://www.azgrowlight.com/products/1000w-double-ended-hps-lamps-high-lumen-efficiency.html

The 1000watt high-pressure mercury lamp is a lamp having the high-pressure mercury vapor discharge coated with phosphor on the inner surface of glass shell. It has soft white light and simple structure, single-ended inflatable bulb with quartz mercury vapor discharge tube. The blue and white cold light provided by the outer oval lamp with inner coating has reasonable light quality, which has the characteristics of the low cost and low maintenance spendings.