Product name: Control knob Size: 1.73in, hole diameter 8mm Easy to install: Our replacement knob can be installed in seconds without any tools, the most important thing is to pull the old knob straight out of the stem and press the replacement knob back into the stem along the direction of the D port. Wide compatibility: Fits most outdoor round vertical propane heaters, mini heaters and outdoor pyramid deck heaters for fireplaces, fire pits, gas grills. Durability: Knobs are typically made of sturdy materials to ensure excellent durability. They are subjected to high temperatures and frequent use, so durability is essential to ensure reliable long-term performance. Extended life: Each set includes 4 durable deck heater plastic control knob protectors that protect the knobs from grease, dirt and wear and tear, effectively extending their life. Keep your knobs looking new and functioning well over time.