Based on this product's specifications, here are some alternatives and similar models
Reduction duct Lindab RCFU 200–125 short with socket/nipple connection
Summary description:
Lindab RCFU 200–125 short reduction for circular ventilation ducts, model RCFU with nominal diameters 200 mm to 125 mm. Constructed for socket (muffe) and nipple (nippel) connection, it provides a compact transition between duct sizes in HVAC systems. Suitable for air distribution, exhaust and supply ductwork where space is limited and reliable, standardized fittings are required.