These Wooden Science Kits drop 20% when you apply code BRAD20 at checkout at Apollo Box. Shipping is free when you sign up for a membership, otherwise it adds $3.50. This is a 20% discount, and there are three different designs, including the Da Vinci Helicopter, a Robotic Arm, and a Da Vinci Tank. Please note that the Robotic Arm and the Da Vinci Tank are slightly more expensive. These kits are made of untreated wood and recycled materials. Sales tax is charged in most states.