They were from a brand called Diamond Audio, not to be confused with Diamond Multimedia of the S3 card fame. Packard Bell had them make proprietary models for their monitors. The main proprietary bit was the mounting lugs that connected them onto the monitors. They were not designed to last, being pretty made of small bits of pretty flimsy abs plastic. When new they could break off with any unfortunate violence, but ABS degrades over time and basically they will have all disintegrated now.

I've been looking for a two-generations older (Symphony-range) Packard Bell A520 or A720 monitor (PB custom design contracted from Tatung or Hyundai) with speaker 'ears' for a while now, but speakers with intact lugs essentially do not exist. I've not looked too closely at the blue Odyssey-range stuff, so there's a tiny chance things may be better there. I doubt it though...