Documents needed from previous employer for H1b stamping

[smneedshelp]

Hello
I am going for a H1b stamping to Matamoros Mexico
I work full time with my current employer
I have had 1 previous employer (consultantancy) which I worked for 7 years.
What documents do I need to take from my previous employer to stamping??

Thanks

[shervin143]

Experience letter from the previous employer and their W2s.