This Seiko 5 model SSK025K was designed and constructed to be reliable, robust, and functional encompassing the Seiko 5 Sports characteristics. With the additional GMT function, it allows you to also track a secondary time zone. With a slimmer and more versatile design this is a perfect timepiece for watch enthusiasts. - Cal. 4R34- 39.4mm Case Size - Screw See-Through Case Back - Three-Fold clasp w/ secure lock, push button release- 100 Meters Water Resistant