CMC Products Power Magazine, 45ACP 10 Rounds, Fits 1911, Stainless M-PM-45FS10 Power Mags are lean and sleek" yet they are extra-heavy-duty with increased reliability and service life. A unique all-steel follower design yields the lowest possible bearing surface for long-lasting function in dirty environments when ongoing cleaning and maintenance may not be possible. The unique follower design also functions as a spring" which allows the high tensile rocket wire spring coils to be the largest (side to side" front to back" and top to bottom) of any extra capacity .45 caliber 1911 magazine.