These devices have been out for a few years now. Several different models and qualities available, some with a USB plug inside, others using Micro-SD cards up to 8GB. Theoretically useful for capturing low-resolution images when carrying a camera or phone is inconvenient. Or a cheap method of monitoring employees for performance and honesty. The pens also write in ballpen with their short refill. No-one would know that they record as the lens, positioned just above the clip, is miniscule.

I purchased 2 Micro-SD models from eBay sellers in China and the UK. They were actually quite similar. Instructions were an appalling translation from the Chinese and hard-to-understand. Battery life is almost zero, whether charged by mains power or via USB. And the clip broke off on one. So unusable in practice; both returned for refunds.

From YouTube videos I have seen the Spy Pens on the US market -- with the USB inside -- seem of better quality. Internal memory ranges from 4 GB to 8 GB to 16 GB.

Does anyone have experience of using these pens, and are they available in Thailand?

I have used one.

The main problem was distance.

To get a good field of view on the video

the pen was to far away to pick up a decent audio.

Another model was a tag for a keyring, looking like a car door opener.

Similar problems there for positioning.