Zevnico 6 Pcs Vintage E27 Lamp Holder, Black Bakelite Edison Screw E27 Lampholder, External Thread Retro Style E27 Light Bulb Holder, DIY Pendant Socket (Black-Pack of 6)

I tested these up to 400c with a soldering iron and they don't melt so very likely to Bakelite or other thermoset resin rather than cheaper thermoplastic. Even the pendant retention ring is the same high temperature material.In another review a '20 Stone Engineer' claims these are faulty because you cannot undo them. Maybe more eyes, less fists. This is a deliberate design feature to include a ratchet so they don't come dangerously unscrewed by unsuspecting users while changing bulbs (one of the disadvantages of ES vs bayonet). This ratchet is a bent up corner of the tip electrode that can be pushed down with an electrical screwdriver to dismantle the unit.I bought these to to refurbish a designer luminaire which sadly had used thermoplastic lampholders that had dangerously degraded over time even though the 150W halogens were within spec. I have high hopes for these which happen to be identical to the more expensive Art Deco Emporium version (also on Amazon) although this item has does not have the useful instructions.

Lovely vintage look, easy to assemble with good instructions. Great price.

Work fine and look fine as well. Little bit cheaply made but they are cheap!

Exactly as described

These are well made American style light fittings made from black Bakelite and they look pretty sturdy, although I haven't fitted them yet.*WARNING*Once they have been screwed shut they CANNOT be opened. They contain 2 internal features that prevent them from being unscrewed but this isn't stated anywhere on the packaging. I had to break on to get it open again so I could understand what was happening. Whether this is a "safety feature" or designed to force you into buying more fittings if or when you need to reposition them somewhere else I don't know, but without modification (which I do not advocate doing) they are a strictly one use item.