Is it a physics lesson, or a lot of fun... or both? Attach Haba's Block and Tackle system to a branch to cart supplies to the tree house, or to the ceiling near the stairs to transport toys up and down - either way, adventurous boys will love it! This block and tackle is equipped with two loose and two fixed reels, which make a quadruple energy saving - in other words, loads lifted weigh four times less! Now that's lifting power! The system can actually withstand loads up to 80kg - just attach the supplied textile tension belt where the supplies need to go (I don't know about you, but are you starting to think it might be a great way to get food shopping up the stairs...?). The set also includes a 6m-long rope (polypropylene) with the other components made of sustainable beech wood. Length of fixed reels - 36cm; loose reels with hook - 34cm. Diameter of reels - 7cm and 10cm. Age guide: from 3-99 years.