To make sure we’re on the same page, here’s the three 5mm upgrade: http://www.niteize.com/productdetail.php?category_id=28&product_id=110
And here’s the 1W upgrade: http://www.niteize.com/productdetail.php?category_id=28&product_id=145
Both go on a two AA Maglite.

So it depends what you want. If you want long runtime (11 hours to 50%) then go with the 5mm. $5.00. Non-focusable. However, I think this is obsolete with today’s offerings.

If you want brighter (6 hour runtime, $12) then go with 1W. However, the 1W is focusable and for $20 total includes a switch (at REI). Put this on dim, and the light will go 36 hours.

I think these upgrades are great if you have an old maglite laying around. If not, imho it’s better just to buy the correct flashlight in the 1st place.

I like headlamps/flashlights that just use ONE battery (AAA or AA for cost reasons and runtime). These are usually lighter, easier to change a battery, constant brightness (no dimming immediately after battery is put in), cheap battery, easily obtained battery, easier maintenance, and one spare battery will not be noticed.

-Barry