TFK Twinner Twist Duo Notice D'utilisation page 8

INSTRUCTIONS FOR USE AND ASSEMBLY
If you use Twinner Twist Duo as Twinner version the short adapter (1)
will be assembled upper right, the longer one (2) lower left. If you use
only one adapter together with the sport seat as siblings version,
assemble only the lower left adapter (2). For attachment of both
adapter, put them on the frames of Twinner Twist Duo and lock them
with the hooks (3). The tubes will be used as basic for TFK car seat
adapters. Please read the assembly manual in the additional users
manual for TFK car seat adapter.
SECURITY BELT
Fig.II:
For all versions, secure the adapters with the red safety belt (3)
around the frame of the stroller and lock it to button (4).