Initial investigations carried out by Hezbollah on pagers that did not explode suggest that Israel placed 1 to 3 grammes (0.04 to 0.11oz) of pentaerythritol tetranitrate (PETN), a powerful explosive, in each device.
In addition, metal balls were placed around the pager batteries, allowing the explosive force to propel metal fragments outward, significantly increasing the lethality of the blast.
https://www.aljazeera.com/news/2024/9/18/how-did-hezbollah-get-the-pagers-that-exploded-in-lebanon
How did Hezbollah get the pagers that exploded in Lebanon?
Al Jazeera traces a pager supply chain from Taiwan to Hungary to Lebanon β including a three-month port layover.Sarah Shamim (Al Jazeera)