The DW4/350 is the Mullard version of this standard rectifier. There is no minimum series resistance quoted and the maximum value of reservoir capacitor is given as 16 μF.
Branded a Mullard product it was made by Philips in Holland.
The two central rods hold the tension springs for the oxide coated ribbon filaments.
The classic envelope is 49 mm in diameter, and excluding the B4 base pins is 114 mm tall.
References: 1043 & 1040. Type DW4/350 was first introduced in 1936. See also1936 adverts.