The Xertube purple (very heavy) resistance bands are perfect for their purpose. The purple band provides resistance equivalent to about 20 pounds. The great thing about this band and other bands in general is their versatility. They're very light so you can take them just about anywhere, which makes them perfect travelling companions. They're much more useful than weights (not to mention cheaper!). With the band, you can do regular curls just as you could with dumbbells, but the band helps you go beyond that! With the band, you can take part in many various exercises that involve the core that are impossible to do with dumbbells. I've always had a strong throwing arm, so it's something I take pride in. Resistance bands like this one help me work on all my "throwing" muscles at one time!