Radial Engine SL

RADIAL ENGINE SL: ENGINEERING SOVEREIGNTY
At five years old, ZBL has achieved what independent watchmakers spend decades 
pursuing—complete vertical integration. The Radial Engine SL is the proof.
Unlike independent brands that outsource movements, cases, or straps to third 
parties, every component of the Radial Engine SL is engineered and manufactured 
in-house in Guangzhou. The movement. The case. The strap. This is manufacturing 
sovereignty.
THE MOVEMENT: PROPRIETARY ARCHITECTURE
The automatic movement at the Radial Engine SL's core is built on the proven Miyota 
9015 platform, extensively modified and tuned in ZBL's workshop. This is not a 
rebranded calibre—it is a platform that ZBL has made its own, representing the 
brand's first step toward a fully proprietary automatic movement. The 21,600 vph 
frequency delivers precise timekeeping. 40-hour power reserve means the watch 
performs across a realistic wearing pattern.
THE CASE: DUAL-SIDED PRESENCE
The 44mm titanium case is the Radial Engine SL's signature. Both the dial and 
caseback are sapphire crystal—a visual statement that the movement is complete 
and worth showing. The dual-sided dial presents the same time on both faces, a 
functional design choice that reflects ZBL's philosophy: a watch should be beautiful 
from every angle.
At 13.5mm thickness and 104g in weight, the case balances presence with wearability. 
The titanium—Grade 5 chosen for its strength-to-weight ratio and corrosion 
resistance—signals that this is a tool watch built for daily wear, not a collectible 
confined to a safe.
30 meters of water resistance acknowledges the real world: splashes, rain, hand-
washing. Not a dive watch. A life watch.
MANUFACTURING SOVEREIGNTY
The Radial Engine SL embodies ZBL's founding principle: that an independent watch 
brand must control its own production to preserve integrity and identity. Every 
technical decision—case geometry, movement tuning, strap comfort—flows from one 
workshop in Guangzhou.
This vertical integration eliminates the dependencies that plague independent 
brands. No waiting on external suppliers. No compromises dictated by third-party 
lead times. No quality fluctuations from multiple vendors. The result is a watch 
that is entirely ZBL.
DELIVERY
First batch production: end of July 2026
Pre-orders deliver: mid-August 2026