1. HSR15-300 mm Linear Guide Rail: This linear guide rail set includes 2pcs 12 /300 mm long HSR15 rail shafts and 4pcs bearing blocks. Sliding blocks are used cooperatively with rails, smooth sliding provided by the inside linear bearing. 2.High-Quality Steel Material: CNC parts linear rails are made of bearing steel, linear bearings are made of good quality steel. The anti-rust surface treatment of the rails makes them durable and extremely hard. 3.Premier Linear Guiding System: Linear guides and rails provide a smooth and precise guiding surface for the sliding blocks. It helps build an economical linear guiding system and is designed to achieve high precision linear motion with a low friction coefficient. 4.Easy to Install: Conveniently install the linear rail by aligning the track with the mouth of the slide rail and pushing the slide rail until the slide rail completely falls. No need for maintenance. 5.Wide Application: The linear guide rail is widely used in CNC Router/CNC Grinding machines, industrial machinery printing, paper-processing, automatic machine, X-Y table, factory automation equipment, etc. 6.This product has two different colors, so you will randomly receive colorful or all-black types. However, they have the same quality, and please rest assured to use them. ******************************************************************************************************* * Specifications Type: Linear Actuator Model: HSR15X300 mm Guide Length: 12 in /300 mm Packing Size: 15 x 5 x 3 in / 32 x 12 x 7 cm Gross Weight: 7 lbs / 3 kg ******************************************************************************************************* *Pakcage Content 2 x Rails 4 x Blocks