If you plan on using your adjustable bench for flat bench variations, be mindful of the distance between the back pad and seat pad (otherwise known as the ‘pad gap’). In general, the three types of weight benches are flat, adjustable incline, and adjustable incline/decline. A flat weight bench is designed with a fixed, flat surface, whereas an adjustable weight bench allows you to adjust the angle of the bench to different incline or, in some cases, decline angles.