Robertson 3P20122 RSS240T12MV /A Fluorescent eBallast for 2 F40T12 Linear Lamp, Rapid Start, 120-277Vac, 50-60Hz, Normal Ballast Factor, HPF (Successor to Robertson 000791 RSS240T12MVIP)

I never swapped out a ballast before this but I just made sure to match up the colored wires and it was a breeze!As you can see from the photo, the old ballasts were from 1972! Crazy!Anyway, these replacements were flawless and very easy to work with. They fit right into the same "slot" that the old ones came out of. Just to recap I used these to replace the "Universal, rapid start ballast, #446-LR-TC-P".

This replaced the bad ballast and is working well.

Robertson is a well-known name in ballasts. I have purchased at least 4 of their electronic ballasts previously, to replace older electro-magnetic ballasts in my basement. The magnetic ballasts eventually demagnetize and stop working, and are heavier, use relatively quite a bit more power, and are generally less environmentally-friendly.This model which replaces the older electronic model ending in MVIP, is almost as good- but not quite. It's a little heavier, and the start-up is not instantaneous; it takes about a second to a second and a half. The MVIP model was near-instantaneous start up. That said, this model is a little easier to install due to the improved design of the slots that you install the nuts to, and due to the wires being longer and stripped.I will buy this again as it's still a quality ballast for a good price - but you definitely want them to address the slight start up lag.EDIT 12/31/2017:One of the two ballasts went bad; I checked the connectors, wires, and electrical connections and they are fine so unfortunately it's the ballast. I won't knock off a star yet till I see what Robertson has to say, but this is surprising. I still wish they continued to produce the -MVIP model, as that one is instant start and has had zero issues over 3 years thus far.

The media could not be loaded.  Replaced two Advance RM-2S35-TP ballasts that were 18 years old. These replacements ballasts work but takes 2 seconds for lights to energize and light the bulbs after switch is turned on. Not instant on start. Fixture in video has 4 40W T12 bulbs that are brand new.

I installed this new ballast in one of three fluorescent lights in my laundry room. It replaced an older magnetic ballast.The new ballast fit perfectly. I needed six wire nuts (not included) to connect to the old wiring.It was interesting to note the difference in weight. The new ballast definitely weighed less.The fixture with the new ballast lit up crisply and quickly. There was a very noticeable difference compared to the old magnetic ballasts, which were slower to light. The difference was so obvious, I bought two more ballasts. They installed just as easily. Now all three fixtures light instantly. Love that.

Works great, eliminated the buzzing from the old and very heavy ballast. However there is a 2-3 second delay.Update: 3/8/2017. Customer Service is non-existent. Tried calling them, e-mailing them, faxing them numerous time without a single response. Amazon will not do anything.

1 of 3 failed withing 2 weeks. Compared to the previous Robertson model it replaces, this one starts a bit slower (about 1/2 a second). You can see it if you have the old and new together. Let's hope for the best for the other 2 and I will report back if I have failures. I note I am running the 40ES bulbs (34W), which can be tougher, but the only ones readily available.

Straightforward to install. Worked as expected. Less expensive than new fixture, and avoided having to paint the ceiling (if replacement fixture had been smaller).