Seiko 6601A, 6601B, 6606A, 6619A,410, 2451, 790 Compatible Mainspring (Incarex)

These Seiko compatible mainsprings are NOS manufactured by Incarex, of France. Incarex had a good reputation for quality but is no longer in the consumer watch parts business. These match Seiko part number 401690, which is compatible with these Seiko movements:

Seiko 6601A, 6601B, 6606A, 6619A,410, 2451, 790 

Type: Automatic with slipping bridle

Height: 1.35mm
Thickness: 0.10mm
Length: 360mm
Barrel Diameter: 9.0mm

Compatibility Notes: I used this myself for a Seiko 6619A. The arbor fit was perfect and after replacement the amplitude was measured at 260.