for a combination of fairly quick plate change , fairly heavy weight capability , fairly short length , & ok solid feel , these will do : although `` Selectec '' , `` Bowflex '' & `` nautilus '' change weight faster & more safely , they be too long , even when set at very low weight , & be not available as heavy db . although `` Ironmaster '' change plate a bit more slowly , they be much more solid , have a design much more functional for a wider variety of exercise , & can be special-order to be as heavy as you want they .