Here is a less expensive check rail mounted window spring bolt. Allows one to lock the window in various positions. Does not include any strike plates. Simply pull up the knob to move the plunger. See below photos of the lock in the retracted and extended position. This lock will also work on patio doors. See also our Deluxe Window Spring Bolt for an alternative.
Base size: 2-1/4" x 1-1/16".
Overall Height: 1-1/4".
Pin extends from a minimum of 3/8" to a maximum of 3/4".
Pin diameter: 1/4".
Center of pin to bottom of base: 5/8".
Includes 2 screws.