Match the model number to your existing belt or pulley system. The H-type model number (e.g., 300H) encodes the number of teeth — multiply by the 12.7mm pitch to get the perimeter. For example, 300H = 300 × 12.7mm ÷ 10 = 381mm... actually, the perimeter is listed directly in each variant (e.g., 300H = 762mm ≈ 30.0"). Measure your old belt's outer circumference, or calculate from pulley center distance, then select the closest matching variant. When in doubt, go slightly larger rather than smaller.

H-section timing belts are generally rated for moderate-to-heavy power transmission relative to lighter XL or L pitch belts. At 30mm wide, these belts are typically suitable for light industrial machinery, CNC drives, and exercise equipment. Actual load capacity depends on operating speed, pulley diameter, and tension. Consult your drive system's engineering specs to confirm the belt is appropriately rated for your application.

The rubber compound generally offers moderate resistance to moisture and mild oil splash, making it suitable for most indoor workshop and light industrial environments. For outdoor use, prolonged UV exposure can degrade rubber over time — shielding the drive from direct sunlight is recommended. These belts are not rated for submersion or exposure to harsh chemicals.

H-type timing belts use the imperial trapezoidal tooth profile with a 12.7mm (1/2") pitch. They are compatible with standard H-section timing pulleys rated for 30mm belt width. Do not use with HTD (metric round tooth) or GT2/GT3 pulleys — those use different tooth profiles and are not interchangeable with H-section belts.

Divide the millimeter value by 25.4. For example: 762mm ÷ 25.4 = 30.0". Each variant shows the perimeter in mm — use this formula to cross-reference with inch-based belt catalogs or OEM part numbers. Common conversions: 508mm ≈ 20.0", 1016mm ≈ 40.0", 1524mm ≈ 60.0".

This is an endless closed-loop timing belt — it forms a continuous seamless loop with no joint. It cannot be cut and re-joined. You must select the correct perimeter variant for your drive system. Open-ended timing belt stock (sold by the foot) is a different product category.

H-type timing belts are commonly found in CNC routers and plasma tables, woodworking machinery (planers, jointers), exercise equipment (treadmills, ellipticals), conveyor and indexing systems, and general-purpose synchronous drive setups where precise tooth engagement is required. The 12.7mm pitch is one of the most widely used imperial timing belt standards in North America.