As someone who regularly binds music sheets and workbooks, this machine has been a game-changer. The 21-hole punching system handles A4 paper perfectly, though I quickly learned to punch 8-10 sheets at a time for optimal results. The metal construction gives it satisfying heft that keeps it stable during use, yet it's compact enough to tuck away on my shelf.

The adjustable margin guide (3mm-6mm range) creates professional-looking bindings every time. Pro tip: Those transparent plastic pocket folders from Walmart? They make perfect DIY covers when trimmed and taped! The releasable punching blades are genius - I often remove some to create custom binding patterns for smaller notebooks.

While it claims to punch 15 sheets, I found 10 sheets works better for consistent clean holes. The comb opening mechanism had me stumped initially (took about 30 minutes of experimentation), but now I appreciate how the lever both punches holes and opens binding combs in one smooth motion.

The included 20 combs get you started immediately, though ordering longer combs is necessary for full A4 documents. My kindergarten teaching materials now look store-bought, and my music collection stays organized without fraying edges. Just remember to 'break in' the punches with the included cardboard first to avoid oil stains!