Text copied from TM9-1985-2 German Explosive Ordnance 1953:

Description: This charge is an assault weapon designed to place on enemy tanks or similar targets, to which it adheres by means of magnets. The body is of paper board and encases the charge and the magnets. A web-carrying handle is attached to the metal neck band. The hemispherical cavity of the hollow charge is closed with a sheet metal liner. Three pairs of magnets are mounted on the inside of the paper board skirt. They are protected in transit by an iron keeper ring which has a web handle fastened to it to facilitate withdrawal. On one side of the keeper are three equidistant spikes so that the charge can be attached to a wooden surface. In transit the keeper is reversed and the spikes are positioned between the magnets. The charge is fired with a 7½-second friction igniter.

Operation: Information is lacking on how the charge is placed and fired. It is apparently designed to be placed by hand on the tank and the igniter pulled after is has been positioned. German documents make no mention of the charge being thrown.

Also known as Haft-Hohlladung Luftwaffe.

Length: 270/273mm, diameter: 140/145mm. Weight: 3000 to 3600gram
Filling 1020gram Fp02-Hexogen 50/50. Brennzünder 7.5seconds (yellow head)
The grenade could penetrate armour up to 130mm.

It seems that two types have existed, a 3kilo and a 3.3kilo model. I have no further info on that.
First tests with the Haft-H (L) by the Luftwaffe were in 1942.

Apparently a 4kilo version Panzerhandmine 4 was also developed.
Four magnets and penetration up to 150mm.