Stainless Steel Fitness Tumbler Design

I'm looking for a creative designer to design a sports and fitness stainless steel bottle tumbler.

Key requirements:
- Primary purpose is for sports and fitness
- Material: Stainless steel
- Features:
- Leak-proof design
- Built-in straw or sipper

Ideal skills and experience:
- Experience in product design, particularly with stainless steel items
- Understanding of fitness and sports needs
- Creativity in functional and aesthetic design

Please provide a portfolio with relevant designs.