I used one exactly like this on the job, for Sig P320 mags. Please see the measurements in the photos.

My .40 S&W Glock double stack mag fits in it as well.

Designed for secure and reliable magazine storage, this Blackhawk! Double Stack Mag Case features a durable matte finish. Its compact size ensures easy portability and access, making it an essential accessory for professionals in tactical and shooting environments.

• Matte finish for a sleek look
• Secure storage for double stack magazines
• Compact and portable design
• Easy access for quick retrieval
• Durable construction

This item is new. It was my spare that I did not use.