1955 is the transition year for Spark Plug socket.

Earlier kits had the Dark Satin Finish with "Hazet" stamped approx. 20mm (this is the spark plug wrench same as the early pre-A of previous years)

Marking: "Hazet" (approx.20mm long)

Marking Direction:

Length-wise, centered on shaft

Length: 238mm (239.4mm measured)

Decal: Hazet decal

Finish: Dark/Dull Silver Finish

Later Kits had the Lighter Silver Satin Finish with "Hazet" stamped approx. 15mm in length

Spark Plug Wrench

Marking: "Hazet" (15mm long)

Marking Direction:

Length-wise, centered on shaft

Length: 24cm

Decal: Hazet decal

Finish: Satin Silver

Tommy Bar

Length: 12cm

Finish: Satin Silver?

<- Note:

The Transition from "L" underline to "straight" underline is blurred. As well as from Darker Plating to Lighter plating from Pre-A to Late Pre-A to Early A. Then, there is a change-over in the size of the "Hazet" logo from 20mm to 15mm in length. Generally, it is accepted that the 15mm Logo and Silver Finish would be found in "Early A" kits. But, older tools could be found in newer kits. However, newer tools would not be found in earlier kits.

The Hazet Schmalkalden plant was destroyed in WW2 (between 1939-1945)

Based on catalog logos:

"U" underline appears prior to 1938: