Velocity Flex Trouser

The term "Velocity Flex Trouser" appears to be associated with specialized firefighter gear. The Velocity PBI Max Bunker Gear, Deluxe Set, features an ergonomic design engineered to provide firefighters with an unrestricted full range of motion. The Flex Knee trousers in this set come with an integrated belt and semi-high back, working together to offer unsurpassed comfort.

If you're referring to a different product, such as casual or formal trousers with flexible features, brands like Arrow offer options like the "Auto Flex" and "Smart Flex" trousers. Arrow's Auto Flex trousers provide additional movement and stretch of up to 2-3 inches with an added elastic at the waist, ensuring comfort and flexibility.

Similarly, the Smart Flex line offers tailored fits with flexible materials for enhanced comfort.

If you have a specific product in mind, please provide more details so I can offer more precise information.