Here's one with a screwdriver in the oval slot: (URL too long to send as
one)
http://g02.a.alicdn.com/kf/HTB1gJElK...8inch-0-200mm-
Electronic-Caliper-Digital-Vernier-Caliper-qstexpress-digital-caliper-
micrometro-electronic-digital-caliper.jpg
--
Dave W