There are many made with many features. I have three different types. One of the simplest is the RAM igniter. You can buy it from Tower for a little over $40. It comes with a 1300 NiCAD, plugs for everything but charging plug. You install your own particular brand of male plug for the charging wire. Don't know why they just don't put on a universal male plug for you.

Expert makes one that is almost infinitely adjustable for about $50.00, without a battery. You have to hook everything up with screw posting wires to the unit.

Nelson makes a "Intelli-glow" (also without battery) that reads the resistance on the plug and provides power as needed (my favorite) you program it every time you turn on the receiver power for where on throttle position you want it to be active. Programming takes about 30 seconds or less. I am buying 4000 MaH, Single C cells from Radio Shack for the ones that don't come with batteries and just quickly solder the power leads to the systems power wires. You can install a mini 5amp switch, also from RS (about $5.00 for a pkg of two) to put between the unit and the glow plug, so the unit can be controlled positively for priming and so on. I have gone to OBG's on most of my planes over .91, since big glow engines, especially inverted can squench a plug when you come off the throttle and then back on too quick, usually when you don't want to go dead stick.

Some folks just hook a switch to a mini or micro servo and a simple battery and use the retract switch to turn the unit on and off as desired. This setup is the simplest, but doesn't give much backup. If you leave it on all of the time, the life of the plug is shortened some.

Happy Landings