Extension Spring, Crescent, TOSTEM, LIXIL, Shin Nikkei, Window Lock, Spring, 3 pieces

This is a replacement spring for the crescent lock used in aluminum sashes built around the year 2000.

The original spring broke, causing the lock to lose its springiness. After searching extensively, I found a spring that fits.

I am listing this product because I believe others may be looking for a similar solution.

Here are some reviews from previous buyers:
It worked perfectly for raising and lowering the lock.
Many people have purchased this item.

Here is a review from a buyer in July 2025:
It worked perfectly for raising and lowering the lock.

We have also received reports that this spring fits Shin-Kikkei sashes from around 1990.

Photo descriptions:
Photo 1: 3 springs that will be sent to you.
Photo 2: My home's window lock (crescent).
Photo 3: Inside the lock, showing the broken spring.
Photo 4: Left: Broken spring. Right: New spring.
Photo 5: Lock with the new spring installed.

Instructions for replacement:
Photo 6: Pry open the lock with a small flathead screwdriver, loosen the screws slightly, and do the same for the bottom screws.
Photo 7: Remove the top screw, move the lock slightly, and then re-insert the screw into the original hole, but not too tightly.
Photo 8: Remove the broken spring and install the new spring. The spring has no specific orientation.
Then, reassemble the lock by reversing the steps.
Please be careful, as screws are easily dropped.

Quantity: 3
Wire diameter: 0.5mm
Outer coil diameter: 3.7mm
Free length: 18.7mm
Spring constant: 0.765N/mm
Material: SWP-B (a type of piano wire)

Additional springs are available for ￥155 each. Please leave a comment.
We also offer a 10-piece set.

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