Lightweight, Accurate, OS Mapping: Why the TwoNav Roc Is My Personal GPS

I sell and train people on just about every outdoor GPS on the market. Garmin, TwoNav, Satmap replacements – they all pass through my hands, and I use them all properly, not just long enough to film a review.

So people are usually surprised when they ask which one I carry myself.

When I'm heading out for a trail run or a long day in the hills, I reach for the TwoNav Roc.

That doesn't make it the right unit for everyone, and I'll say so plainly – if you want AA batteries and buttons only, it isn't the one for you. But for the way I navigate, it does everything I need and almost nothing I don't.

In the video below I take you through it on the device itself, so you can see exactly what I mean.

120g isn't a detail. It's the whole point.

Carrying an extra 100g on a day walk? You'll never notice it.

Six hours into a run over rough ground, you will.

The Roc weighs 120g. It sits in one hand without feeling like a brick, and it still gives you a bright 2.7-inch screen you can read while you're moving. That balance between portability and usability is harder to find than you'd think.

A small screen doesn't mean small mapping

This was the one thing I was unsure about before I started using it – would the mapping feel cramped?

In practice, no. Run it in full-screen map mode and the viewing area is bigger than the spec sheet suggests, and the display is bright enough that Ordnance Survey mapping stays clear even at pace.

Mine is the version loaded with full 1:25,000 Ordnance Survey mapping. That's the detail you want when you're working out footpaths, rights of way and open access land, rather than simply following a line on a screen.

You can make everything easier to read

You're not stuck with tiny text and fixed layouts. The Roc lets you set it up for your eyes:

• Increase the menu text size
• Choose how many data fields are shown
• Build your own custom data screens
• Display a full-screen grid reference
• Use a larger two-field layout for easier viewing

It sounds like a small thing. Out on the hill, in poor light, with rain on the screen, it isn't.

Set your route up so you can't miss it

Everyone sees colour differently, so being able to change how your route looks matters more than most people expect.

Mine is a thick yellow line with a black outline. Against OS mapping it's unmistakable, at a glance, without stopping.

You can adjust:

• Route colour
• Route thickness
• Recorded track colour
• Position icon

The best off-route alert I've used

Most devices give you a fixed off-route distance and that's that. The Roc lets you decide how sensitive it should be.

If you're someone who drifts slightly off a path now and then without wanting an alarm every time, simply increase the alert distance. You can also choose whether the warning repeats every few minutes until you're back on the line.

For trail running and mountain walking, that's genuinely useful rather than just another setting.

Accuracy – and one thing worth knowing

The Roc uses multiple satellite systems at the same time:

• GPS
• Galileo
• BeiDou
• SBAS / EGNOS correction satellites

Even indoors while filming, it was reporting around 2 metres of accuracy, which is impressive.

Battery life that covers a proper day out

Around 18 hours with the screen permanently on and the backlight at roughly 50%. For almost any day walk or trail race, that's more than enough.

The touchscreen can also be locked when it's raining while the physical buttons keep working – which matters, because British weather is the only weather I get to test in.

Why I keep coming back to it

There isn't one standout feature. It's everything working together:

• Lightweight and genuinely compact
• Accurate
• Fully customisable
• Easy to read on the move
• Excellent for following a route
• Available with detailed Ordnance Survey mapping

After thousands of hours navigating with just about every unit on the market, it's simply the one I enjoy using most.

That counts for more than a spec sheet.

Should it be your GPS?

Maybe not, and I'd rather tell you that now:

• If you want weeks of battery from AA cells and button-only operation, look at the Garmin eTrex range instead.
• If screen size is your priority, the TwoNav Terra or Cross Plus give you more to look at.
• If you're brand new to GPS, TwoNav's software rewards a bit of learning. That's exactly why every unit we sell comes with our own training videos, telephone and email support included – no extra cost, no hard sell.