HOT GLOW PLUGS (for low nitro and FAI fuels)
Enya: #3
Fox: Miracle, Standard, abd R/C Long (2V)
Fireball: Hot 1.2:.3.0V , and S-20 R/C Long
FirePower: F6 (warm), F7 (hot) K&B: 1L
McCoy: MC 55 R/C Long, MC 59, and MC 14 (very hot)
O.S, ENgines: #0, #1, #5
Rossi: Rl{extra hot), and R2
SonicTronics: Glowdevil#300
Thunderbolt: R/C Long

MEDIUM GLOW PLUGS (for lO%-15% nitro fuels)
Enya: #4 (medium Hot), and #5 (medium cold)
Fireball: Standard (1.2-2.0V)
FirePower: F5 {medium), F6 (warm)
Fox: R/C Long (1.2-1.5V), and Gold
Hangar 9: Sport Long
McCoy: MC 50, and MC 8.
O.S. Engines: #A3,#8, #9, #7 (w/idle bar)
Rossi: Medium, and R-3
Sonic Tronics: Glowdevil Standard
Tower Hobbies: Performance plug

COLD GLOW PLUGS (for high nitro; 25% and greater)
Enya: #6 (cold)
Fireball: Cool (1.2-1.5 V)
FirePower: F2 (extra cold), F3 (cold), andF4 (cool)
Fox: R/C 1.2 V and #8
K&B: Long & Short Hi Perf Nitro Plug
O.S. Engines: R-5
Rossi: R4 (cold) and R5 (extra cold)

FOUR-STROKE GLOW PLUGS (hot)
Fox: Miracle Plug (often used in 2C's w/low nitro)
McCoy: MC 14 (very hot, often used in inverted 4C's)
O.S. Engines: Type F
Sonic Tronics: Glowdevil ST 301/302

This list is provided courtesy of Brian Cooper, of Cooper Fuels.