The Maars 20oz "Cyclist" Tumbler is noted for its 18/8 stainless steel construction, double-wall vacuum insulation that claims to keep liquids cold for 24 hours and hot for 12 hours, and a sleek design that may fit standard bicycle bottle cages. It's available in a budget-friendly price range of approximately $10–$20.

Yes, it can be useful for triathlons, particularly for training and transition use due to its strong insulation and budget-friendly price. However, it may not be the best primary option for in-race hydration during an IRONMAN or TT events due to its non-aerodynamic design and lack of squeeze/bite valves.

The tumbler’s diameter is approximately 2.75 inches, which should fit many standard bike bottle cages. However, it's advised to measure your cage or test it before race day to ensure compatibility.

The key advantages are its affordability and similar insulation performance to premium brands like YETI or Hydro Flask, but at a significantly lower price point. It's a cost-effective option for everyday training and travel for triathletes.

Consider its fit in your bike cage, and practice using the bottle for efficient on-bike handling to minimize time loss during transitions. It’s also important to choose a secure lid to prevent spillage during the race.

It is best used as a supplemental insulated bottle for carrying cold fluids during training and races, or for pre-race hydration and post-race recovery drinks. For race-day, especially long distance, rely on a combination of hydration strategies including aero/squeeze bottles.