If using with a heavy duty drive then you MUST use a continuous chain ring (See section below)
CONTINUOUS BEAD CHAIN - IMPORTANT SAFETY NOTICE:
When using a standard chain drive the continuous chain must be fitted with a chain tensioner (CHSAFE-R) screwed to the wall no lower than 150cm from the floor. If the chain drive is with child safety breakaway then the chain may be no lower than 60cm from the floor.
State the exact length you would like the chain in the box provided.
To calculate maximum allowable chain length to comply with child safety regulations:
Chain Drive WITHOUT Child Safety Breakaway
Max drop of chain = (Height of headrail from floor in cm - 150cm) Length of chain = drop x 2
Chain Drive WITH Child Safety Breakaway
Max drop of chain = (Height of headrail from floor in cm - 60cm) Length of chain = drop x 2