The LEGO Technic App-Controlled Cat D11 Bulldozer (42131) set is a must-have for any fan of construction vehicles. This impressive model allows you to build a replica version of the biggest Cat dozer, complete with modular sections and a new-for-2021 LEGO element - a large track that can be tightened and loosened. Once built, the set comes to life with the CONTROL+ app, allowing you to operate the heavy-duty machine with realistic movement and functions, including raising, lowering, and tilting the blade or ripper and ladder. Not only does this set provide a rewarding building experience, but it also allows you to explore engineering concepts in an accessible way. With authentic colors and graphics, this meticulously detailed Cat dozer is a top gift idea for any enthusiast. The model measures over 10 inches high, 22 inches long, and 14.5 inches wide and requires 6 AA batteries (not included) as well as 2 no. 15 motors, 2 large motors, and 1 hub. The LEGO Technic universe offers advanced buildable models for immersive building challenges, and all components meet rigorous industry and safety standards. Overall, the App-Controlled Cat D11 Bulldozer set is the perfect combination of fun and education for anyone who loves construction vehicles.