[SPRING DIMENSION ]:One set garage door spring of 0.250??? springwire size x 2??? inside diameter x 29??? length Garage Door Torsion Spring included left garage door spring and right garage door spring. Also stationary and winding cones included. Our ISO9001 qualified factory with strict QC control could guarantee you correct spring size and excellent quality. [EXTRA FREE PARTS] : A pair of Garage Door Torsion Spring, A pair of 17.2?????? Non-Slip Winding Bars and Gloves/Eye protector/Professional wrench/Mini plastic Vernier Caliper, and Installation Instructions are included in the package, with the professional tools DIY is much easy to learn installing after receiving the product. [NEW TECHNOLOGY ]: Made of 320 ??? heat-treated professional spring steel coils with stronger aluminum cones to make sure they are extremely heavy duty. The latest cataphoresis coating technology provide excellent corrosion proof performance and superior abrasion proof performance, especially less noise technology adapt. Salt spray tests up to 360 Hours, and 10 years lifespan for housing using each days 5 times. Always keep springs shinning, no need to lubricate the spring anymore, keep hands clean during installation. [EASY TO INSTALL ]: DIY design for the installation manual with clear photos, with new high quality garage door torsion springs to replace old broken garage door spring.The most damage of DIY garage door spring is to avoid the spring swing itself and other parts move itself. With professional tools and read the installation manual and video carefully. Good experience of installing torsion springs can save you a lot of money. [AFTER SERVICE] : We???ve marked clearly the spring-steel-wire diameter/inner diameter/spring length on our spring products. The principle to select new springs should same size as your original one. So please make sure that the wire diameter, inner diameter, and length of the spring you choose are exactly the same as the original spring used. We have after service team in CA and Chicago, any question please contact us freely will reply you 24 hours response time.