A sight is fastened to a bow essentially in one of two ways. Either the sight arm is mounted by screws directly to the bow, or a block is mounted to the bow, and the sight arm slides in and out of that block. With a slide-in, slide-out sight, you can easily move the sight to adjust your sight picture through your peep. That is, you can adjust the sight so that when you look through the peep, the scope perfectly fills the peep. You get the scope ring to match the peep ring to know you are aligned. Also, slide-in, slide-out sights can easily be removed for transport in a case. Turn a knob, and the sight slides out. Direct-mount sights may or may not have multiple mounting positions to try to match the scope to your peep. If one doesn’t, then what you see through the peep is what you get. Your only option then is to change peep sizes. However, you never have to worry about a direct-mount sight sliding because the holding knob came loose. The screws hold it in place. Period. They also tend to be quieter due to the direct connection.