Gisafai6 Pcs Extension Spring Steel Dual Hook Construction Tension Springs with Hook Ends for Machinery Repair Industrial Garage Door DIY (3/8 Inch X 6-1/2 Inch,0.047 Inch)

The springs are decently springy. Seems to be made of standard material. They are quite long as well. They are not very strong though. They can be stretched out completely by hand and do not create much tension. So the overall spring construction is rather thin.I believe these would work well in light duty applications like for a storm door. Would not count on them being able to handle any item over 10lbs or so.

I use them for a sun shade, and they give a little with the wind, instead of turnbuckles which rip out the islets.

I used these springs to replace bungy cords holding tarps on both ends of my pole batn. Every few weeks I had to change bungy cords as they would sun rot and break from over use. I use these springs now in place of the bungy cords and have't the need to change them anymore unless they rust, which should take a great length of time.

I bought these springs for an old drafting lamp. I've had this map for like 20 years and don't really want to get rid of it, but the springs are all worn out. I've been using rubber bands to bolster the springs, but that's janky and the bands snap after they dry out. I finally found some springs that fit. They took a little work to get on because they're nice and tight, but once I did, the lamp's swing arm feels brand new, lots of smooth articulation.

It is very strong and sturdy

Love it? I hung whirlwind

These extension springs are well made and were the perfect size for my project. No issues with the springs and they are sized to the product description.

...a lot of work and often lose their strength. Used these to repair an old magnifying work lamp.