Which size works?

[The Worksop Heel Bar 39]

Customer wants a new works for this watch and have looked on cousins but not sure which of the 5 works they have is the right one. Any ideas?

 

Y121E

[Lee 748]

That's impossible to say without measuring things. Height1 is the most popular. Start there! You can see the differences under an eye glass, just check before fitting