The photo below shows my great-grandfather Harry O'Brien on the left and his son Lowell on the right. In the middle is an unknown musician holding a clarinet, perhaps visiting the shop to test one of Harry's crystal mouthpieces. The photo is undated, I am guessing 1940s. If anyone has an idea on who the musician is, please feel free to comment on the blog.
Photo Source: Mike O'Brien - Harry, Lowell & an unknown musician