The PN-40 is currently DeLorme's entry-level GPS. It has been available for several years as the top model, and was a major upgrade to the PN-20. An intermediate model, the PN-30, was available for about a year as the PN-20 was phased out. With the introduction of the PN-60, the PN-30 has been phased out as well, leaving the PN-40 as the low-end model.

The PN-40 has a dual-core processor, and 512 megabytes of on-board RAM. It can be expanded using SDRAM modules up to 32 gigabytes. It has a color screen with 220 x 176 pixels resolution, and 65K colors. It has a built-in electronic compass and barometric altimeter. It has all of the standard GPS features like being WAAS-enabled and waterproof. It has an immensely customizable feature set, and comes with all of the map data that you need to use it, right out of the box.

The PN-40 is one GPS that does it all. Compared to most other GPS devices, it is possibly the most economical one available. In the box, you will get a full set of maps on 5 DVD's, with 1:100,000 scale topographical maps, plus road, street and POI data, for the entire USA, plus most of Canada. Some coverage of Mexico is provided, but nowhere near as comprehensive as USA and Canada. It includes the 8.0 version of DeLorme TOPO USA 8.0, available seperately for aroun 100 dollars. With a DeLorme Map Library subscription costing only 30 dollars for a year of unlimited access, you can have practically all of the topographical map data, aerial imagery and satellite data that you will ever need.

TOPO USA 8.0 is one version of DeLorme's flagship electronic mapping product. It has been supplanted for the most part by TOPO North America 9.0. It has detailed maps of the entire United States, plus added data for Canada and Mexico. It also includes all of the street-level data from DeLorme Street Atlas 2009, including millions of points of interest such as hotels, restaurants, and recreation attractions. The vast amount of data makes the PN-40 an extremely valuable GPS for the money. The optional map library subscription lets youget aerial and satellite images of almost any place, and unlimited 1:25000 USGS Topo maps. TOPO USA is also the software that manages the track and waypoint data on the PN-40. It is a bit difficult to understand and use, especially for the non-technical user. Read our review of TOPO USA 8.0.

The PN-40 has highly customizable menus, which control access to its numerous feautures. It has its features divided among a number of screens which include routes, tracks, sun/moon data, compass, altimeter, GPS coordinates, diagnostics, and many morel. Every screen, except the map screen, can be omitted from a paging sequence. The paging sequence can be ordered in any way that you choose. Almost every screen can be customized as to which data fields you want to see, it has seemingly dozens of data fields available, such as coordinates, date and time, altitude, and many more. Some of the more obscure fields are time spent moving and time sitting still. It can display odometer and time or distance to a destination.

If there are any drawbacks at all, they would have to include the tiny screen size. The screen is average for GPS units, but it is too small to do any justice to the aerial and satellite imagery. It does acceptably well with the DeLorme TOPO USA 8.0 maps, and the downloaded USGS maps. The biggest flaw with this device is the short battery life. Carry a set of spare batteries with you, and don't try to use the same batteries for 2 days in a row without recharging them. Alkaline batteries do much better than rechargeable batteries, but come with a higher environmental cost.

The PN-40 works a lot like a Garmin, so the learning curve is reduced for anyone considering changing GPS manufacturers. The data that is included is comprehensive and exhaustive. There is not very much missing. Available accessories include a Travel Power Kit, consisting of a Lithium Ion battery, an AC adapter, and a 12-volt car adapter. A handy carry case with a very secure belt clip is also available.

Nerds in the Wood thinks that this is one of the best GPS values available to hikers and geocachers. It works well in the field, and the customizability adapts it to specific functions quite easily. With the exception of the TOPO USA 8.0 software, it is aesy enough for anyone to use, and with Cache Register, it is a premiere geocaching solution.