Which printers does this adapter fit?

It is specified for the Zebra GK420d desktop label printer. Check your printer's model and power input before ordering, since other Zebra models use different adapters.

Is 70 watts enough for the GK420d?

Yes. The adapter is rated at 70 watts, which covers the GK420d's requirements. An underpowered supply can cause print dropouts or the printer failing to power on.

Can I use a generic 24V adapter instead?

Often yes, if the voltage, current rating and barrel connector match. The trade-off is that a mismatched plug or lower current rating can cause intermittent faults, so match the specs carefully.

Does it come with a power cord?

The adapter is the power supply unit itself. Whether a wall cord is included depends on the specific listing, so confirm the contents before buying.

Is this the right part if my printer won't turn on?

It is the usual fix when the printer is dead and the outlet and cable are fine. Test with a known-good adapter first to confirm the supply is the fault.