Excellent practice amp at a very modest price. The Spider IV has 4 onboard amp models, and countless others you can tweak yourself. You can choose from shimmering clean tones, a classic crunch inspired by a 100-watt Marshall Plexi, and a punchy high-gain inspired by a Mesa/Boogie Dual Rectifier. Line 6’s award-winning effects include a tap tempo function that allows you to sync up your effects with on-board Tap Tempo. With two pushes of the Tap Tempo button, all of your time-based effects precisely fall in with the beat. The peaks of your Tremolo will match the feedback of your Sweep Echo, etc. In all the Spider IV 15 features 6 Smart FX including a Chorus/Flange, Phaser, Tremolo, Sweep Echo, Tape Echo, and Reverb. After your choose your amp and effects you can create up to four custom-made presets you can save each to a Channel memory and recall it instantly with the touch of a button. You can recall instantly via pushbuttons, or connect an FBV Express MkII or FBV2. Other features include built-in tuner, 1/4-inch input; 1/4-inch headphone/direct output; 1/8-inch CD/MP3 input; and FBV jack. The amp’s ¾ closed back is tighter, with more punch, compared to an open back design. This is a lot of amp for $55.