Made of high bearing steel, deep groove ball bearings. Widely used, economical and standard bearing. Less friction, higher speeds and durability. Special non-contact double rubber seals to seal out dirt while providing friction-free performance. Easy installation and replacement. Item Name: Ball Bearing Bearing Type: Blue Sealed This bearing kit was designed to replace all bearings of the models below: Redcat Volcano EPX Pro Redcat EPX Pro Material: Metal+Rubber Color: Silver+Blue Package Content: 8 x Bearing (5x10x4mm) 8 x Bearing (10x15x4mm) 4 x Bearing (12x18x4mm) Only the above package content, other products are not included. Note: Light shooting 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 +/- 1-3 cm.