So, I've had this pair of pickups in a one-off hollowbody since the late '90s and I've never been able to identify them. They sound fantastic -- super articulate and touch-sensitive. They were in a beat up Norlin LPC that a local Fort Worth guitar store was selling somewhere around '98-99. They swapped in three new pickups for the Gibson and sold me these mystery units for $40. That's about all the backstory I have -- the covers looked worn about like they do now back when I got them. If I had to guess, I'd bet they were from the '70s-80s. The bottoms look like they've got slug poles of varied height on each coil and maybe skinny bar magnets across them. Bottoms are sealed in a kind of semi-hard rubbery substance. Seems more like that tool handle stuff than epoxy.