Yep, Empty Chamber Flag for use at the range. Ranges that require chamber flags often provide them, so I've heard.
My LCP doesn't lock open and a chamber flag would be sweet. I'll toss a weed whacker string in my bag. Great idea!
.45acp, .40 S&W, 9mm, .38 Spl, .380 acp, 22lr
12 gauge, .223/5.56x45mm, 30-30 Winchester
2 Chron. 7:14 Christians must seek His face