The "heavy metal" category for VIBROPLEX keys.  VIBROPLEX double keys are manufactured with the same top components as single keys in various base configurations.  These are made to stay put on the desk - the minimum weight of a double key is nearly 7 pounds of steel. 

Be sure to navigate all three pages at the links below.

Iambic/Straight Key Standard double

Iambic / Straight Key Deluxe double

Vibrokeyer / Straight Key Standard double

Vibrokeyer / Straight Key Deluxe double

Dustcover, double keys

2 wire cable - 1/4 connector

3 wire cable - 1/4 connector

3 wire cable - 3.5mm connector