I dont think they will fit as i have had some run ins with changing the insides on my light.I got an arcadia series 3 with 3 250w MH and one burnt out in the second month.They took it away and tryed to fix it buy replacing the whole inside of the unit.It came back looking like a guy wearing a t shirt 5 sizes to small.This was already a 250w and they didnt fit so i think the 3 series is thinner.Never know your luck,could be a winner