This is the switch you will want to power up to two of your grow lights. We have two of these units for sale. Each unit will power 2 Ballasts. One is unopened in the box brand new. The second unit was used for only 9 weeks and is in mint condition. If you buy both of these units then you are good to manage 4 Ballasts.
240 VOLT POWER EXPANSION MODULE “SENTINEL” BRAND PXM-2 (For use with up to 2 Ballasts)
