Strap for Nav B-Uhr 44 Automatic B-Type

The lug width of the Steinhart Pilot F0313 is 22mm, measured from the internal point of one lug to the internal point of the other. This measurement is essential for selecting a compatible strap. To verify the measurement with precision, use a digital calliper positioned between the two lugs on the internal side of the case.

The best strap depends on intended use and personal preference. For authenticity to aviation heritage, a NATO strap in regenerated textile fibre is recommended: it offers stability, comfort over thick jacket sleeves, and genuine instrumental aesthetics. For elegance and durability, vegetable-tanned calf leather with natural patina is superior to pure alligator, as its tighter grain ages magnificently over time. FKM rubber is the most versatile choice for humid environments and intensive use.

Strap replacement requires gentle removal of the lugs. Position the watch on a soft surface (rubber mat or cloth). Using an appropriate tool (spring bar tool), slightly compress the internal spring of the lug to make it spring out from the case hole. Repeat on the other side. Avoid abrupt movements that could scratch the satin steel. Insert the new strap by first aligning one end, then gently compress the spring and snap the lug into the other hole.

Yes, all straps with 22mm lugs are mechanically compatible. However, true compatibility is aesthetic and functional. A high-quality strap (vegetable-tanned leather, NATO in regenerated fibre, FKM rubber) preserves the instrumental vision of the F0313, whilst inferior-quality straps or inappropriate colours compromise the watch's identity. Favour specialised suppliers who understand this model's aviation heritage.

A vegetable-tanned calf leather strap, with proper maintenance, lasts 3–5 years of daily wear. Durability depends on three factors: leather quality (calf surpasses alligator in longevity), usage frequency (alternating with other straps extends life), and environmental exposure (high humidity accelerates ageing). If treated with natural conditioner (pure lanolin) every 6–12 months, the strap develops authentic patina and even longer lifespan. Final fibre deterioration is natural and marks the transition to a new strap.