Great question - but just a note to potential respondents: please keep any recommendations limited to your own organisation's experience (ie: this is a non-commercial forum, so we don't want suppliers of lone worker solutions piling in ...)

The two types of lone work that are the highest level of risk for our organisation are truck drivers operating self-loading logging trucks and fertiliser trucks working in remote areas that are steep and with no phone nor RT coverage. We've looked at rollover devices and man down devices but opted for a small portable device called a Spot Gen 3. They work off satellites and have a check in mode, can use a customised message and also have an SOS button. They also have a tracking system based on google maps. Hope this helps.

Hi. Yes we're a supplier (albeit hardware agnostic but we do supply some devices). I'm sure Peter knew I'd be wading in, uninvited :) Because I'm passionate about knowledgeable advice based on real experience. We are not fans of Spot devices in a commercial environment.

There are a number of independent reviews which have been done; copy and paste the link below for a really thorough review.
https://www.outdoorgearlab.com/topics/camping-and-hiking/best-personal-locator-beacon

Good question. I had the same problem. Are there any analogues of the Spot device? And if such devices are available, then what is the cost of these devices?

It really depends on your risk for example would a phone app be adequate or do you require something more advanced. We have different devices for different areas, non-require check ins as this is to open to human error.

Take a look at verisafe.co.nz . I like it because it's simple, transparent and it works.

I agree with Brian - Verisafe is a great system and a not for profit organisation built on providing a call for help for domestic violence sufferers. Contact Hannah Millward for a run through: hannahatverisafedotco
We're about to trial a small device called a "flic" https://flic.io/ for receptions and alike - you can programme it to do a multitude of things and use other software to send messages, emails, or sound alerts in other systems. Doesn't have the installation costs of monitored systems or the monthly bill.

We have been looking or some robust outdoor gear and have had a lot of support from Entec

Try vault Solo it's a great Lone Worker Platform.
Vault Solo

Depending upon your industry, Solo Protect may be worth a look

Tait put out a good system...

We use Trackme. They would well and the send a message to a call centre for callbacks and then escalation.

If I can add my two cents worth, whatever you choose it must be 2 way otherwise once the novelty wears off users will get slack and stop using it. I know that because I checked not feedback no work.

I usually get my clients to use a combination of the 'Get Home Safe' App and Garmin 'In Reach Explorer'. This is a GPS with an SOS tracking function that's not far off military-grade and is surprisingly cost-effective. It also has messaging to email and mobile phone through satellite capability so you can Bluetooth the device to mobile if you need to.

This is not the perfect solution for everyone; however, and based on a presenter that I heard speak at the Southern Safety Show (Invercargill) and my own experience I think you need to consider the following:

1. What is the risk category that your worker is in?
An accountant doing a site visit will not face the same STICKY (Stuff That Can Kill You) that a transmission line worker will. The line worker may require an on body product that can tell if the person has collapsed or taken a fall.

2. The availability of mobile and other communication networks
Understand the coverage available and how reliable it is

3. Response time required. Do you need 24-hour monitoring from a call centre such as St John to ensure there is a prompt response?
What is the typical work schedule? Is it 24/7 or emergency response only?

Hi there, we use Buddi as our lone worker system.
It comprises of a GPS monitored clip, and a 'watch' that users wear to raise the alarm if needed, and a base for charging.
The clip is a one-way voice system that connects to the St John monitoring centre when activated. They listen and determine the course of action based on what they hear.
Behind the scenes there is a portal where you can manage devices/users, see where units/users are (if needed) etc.

Our risks are workers having face-to-face meetings with potentially aggressive customers away from the office (and it's controls).

Happy to chat if you want to know more about how we use it etc.