The Helios FM 250 is a high-quality flexible sleeve designed to minimize vibration transmission between fans and ducting systems. Compatible with matching FR flanges mounted on fan spigots, this connector enhances installation stability and acoustic performance. Supplied in pairs, each sleeve includes worm screw clamping bands for quick and secure attachment. Suitable for duct sizes ranging from 100 mm to 710 mm, it’s an essential accessory for reliable and quiet ventilation setups.