Battery Tender brand is the most popular. I have 2 chargers, a Battery Minder +, which has a "desulfater pulse" built in. I can't attest to the success of the "desulfator pulse", but it makes me feel good seeing the light flash.
I also have a Yuasa, which I do not recommend. It doesn't seem to have a maintain cycle, and will boil a wet cell battery dry (you have a sealed batt.). Almost all tenders have the SAE connector (look at a pic before buying) and an extention with alligator clips for other batteries. Yes, they just plug in and do their job.
Ebay is an easy place to compare 12v charger features and prices, then buy local or on-line.