BIRD Digital RF

Same as SK620A excepct for modified bypass capacitor.
1500pf Bypass capacitor, 1000DCWV
Socket has a chimney siliconed onto it. 
New old stock * No longer available for export
MFR: Eimac
SKU: Y268

Tube socket designed for the 4CX1000A and 4CW1000
Used
MRF: Eimac * Made in USA 
SKU: SK-810-P

Designed to function as a conductive bracket for the bottom of the SK-300A 
Used * No longer available for export
MFR: Eimac
SKU: MCMR

Designed to function as a conductive bracket for the bottom of the SK-300A 
Used * No longer available for export
MFR: Eimac
SKU: ICMR

Designed to function as a mounting bracket for the base of the SK300. Generally used to fasten a cable to the base of the socket to run power through.
Used * No longer available for export
MFR: Eimac
SKU: RAMB

Designed to function with 4CX5000A, 4CX5,000R, 4CX5,000J 
Used
MFR: Eimac
SKU: SK300-P

Designed to function with 4CX5000A, 4CX5,000R, 4CX5,000J 4CW10,000A 4CW10,000B 4CW10,000R, 4CW25,000A, 4CW25,000B, 4CPW10,000, and 4CW30,000A tubes.
Same as Y-291 except for bracket placement.
New Old Stock
MFR: Eimac
SKU: SK300

Similar to 4X150A with coaxial base. Max frequency raised to 500MHz CW or to 1500MHz pulse.

New Old Stock * No longer available for export
MFR: Eimac
SKU: 4X150G-EI-NOS

Bypass capacitor 2500pf. 1000DCWV
Air system socket. Heavy filament leads. Same square mounting plate as the sk SK840. No tube elements are grounded
Used
MFR: Eimac
SKU: SK-831-P