The slider works by pressing a button on the side. Each hole is split in half and pressing the slider closes the top half and opens the bottom half. So my 10 hole chromatic basically has 20 holes. It's sort of like bending by giving you extra notes but without the bendy sound. On this kind of harmonica there are no missing notes. Music is fun even though I'm not the best at it! I'm imagining all your ukuleles hanging up in a row on your wall. I didn't know there was such variety among them but it makes sense. Thanks, you bet I'll keep riding those waves!