I went through three or four WM, or WM style boat hooks. Junk IMO. They don't like water, especially salt water. Their cheaply anodized surface will start to corrode, making it difficult to slide their telescoping sections.
Instead, I recommend either the Swobbit (previously mentioned) or Shurhold's line. Their telescoping handles gained fame in washing boats (they were designed
for water intrusion), and have a multitude of nifty accessories you can clip on the end, a boat hook being one of them. And another plus if you're a cruiser; one less item to stow.