Geomag STEM Master Box Silver Rods (248 Piece) Stacking Toy MAGNETIC ENGINEERING - This playset contains 144 yellow magnetic rods and 104 non-magnetic steel balls that let you connect and build awesome creations you want. Make an architecturally sound bridge! EDUCATIONAL AND STIMULATING - Goma's award winning line of products help children of all ages develop imagination and curiosity through the science of magnetic construction. STEM learning product ASSURING SAFE PLAY - manufactures to the most rigorous safety standards. At our facility in Switzerland production is monitored through each phase to adhere to the highest safety standards SPECIFICATIONS - Recommended for children ages 3 and up. Warning: CONTAINS STRONG MAGNETS. Keep away from sensitive devices such as credit cards, computers, and medical devices like pacemakers