The RL2P3 is a battery pentode. The data-sheet refers to it as a transmitting pentode for use in the low VHF region. The maximum anode dissipation is 2 Watts.
The valve was made by Valvo for the unified German military during the time of the Nazi regime 1935 - 1945. The wording Wehrmacht Eigentum and logos make this clear.
The Valvo name on the Bakelite knob on the end of the envelope. The design was for a valve that could be swapped out in the field without dismantling the set.
The brass pin connects to the control grid. The other connections are studs mounted around the base.
The base with locating key at the top.
The wide metal tube envelope is 30 mm in diameter, and excluding the base pin is 96 mm tall.
Reference: Data-sheet. Type RL2P3 was first introduced in 1936. See also1936 adverts.