Comment by panarky
I don't know the density of PETN and I'd prefer not to fire up a VPN to run that search at the moment, but let's assume it's something like 1.5 g/cm³
So 20 grams of the stuff would occupy 13.3 cm³
Which is equivalent to the volume of about three and a half AAA batteries.
How big are these pagers, and how can there be that much empty space in one?
Specs:
- Dimensions (mm): 73(L) x 50(W) x 27(H) (98.55 cm^3)
- Weight: 95g including battery
Presumably the majority of that weight is battery. And 13.3 cm^3 would occupy less than 1/6 the total available volume.
Battery is described as "Lithium battery, up to 85 days with 2.5 hours for full battery charge, USB-C charging."
From: <https://www.gapollo.com.tw/product/ar-924/>
Archive: <https://archive.is/Kw0Pg>
(For some reason the origin is unreachable presently.)
From comments and news stories elsewhere, it seems highly probable that the explosive was engineered into a battery form-factor, and replaced the original battery of the device.