Thickening treatment, reasonable transition, suitable for transitional connection in the pipe. Made of high quality material, environmentally friendly, non-toxic and hard. Easy installation, using duct tape or duct clamps to connect air duct adapter. Perfectly suited for bathroom, kitchens, apartment, home, office, hotel HVAC system. Perfect to connect 150mm to 100mm duct system. colour:White Material:plastic size: φ150-100mm, upper diameter 97mm, lower diameter 155mm, height 117mm Package Contents: 4 x Pipe Adaptor Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.