Semi-permanent needles?

[GabrielePfr]

I've obtained a box of some curious needles and can't find much information about them.
They look like Laubscher Unica, and those were advertised as long-playing, 20 records or so. I am wondering if all needles of this shape are meant to be played a few times, thus the different construction. I played one and it sounded good, the needle didn't show much wear. I'm worried I'll damage my records if they're unusually hard, and shouldn't be used, at all. Looking forward to any information you might have!

[Lucius1958]

What age are they? They might have been intended for lighter electric pickups, rather than acoustic soundboxes.

Bill

[wjw]

I had lots of these years ago and used them on Victrolas. I thought the sound wasn't quite as clear as a regular spear point needle. Maybe too much "compliance" from the design. They needle wear after one play looked like any other steel needle and I changed them each time.
-bill

[GabrielePfr]

What age are they? They might have been intended for lighter electric pickups, rather than acoustic soundboxes.

Bill

I don't really know, it says Delagrange on the lid but I was unable to find any information online. The plastic doesn't seem to be too early.

[De Soto Frank]

These look like Recoton needles I've seen over the years.

Good for only one side on an heavy acoustic reproducer.