It is a four piece design that uses the transformer itself as a structural member and is configured so the transformer connections are readily accessible without removing the whole assembly from the chassis.
Lundahl Metal Housing, LL1620-housing
Lundahl Metal Housing, LL1638-housing
SB Acoustics Satori Beryllium TW29BNWG-8 Tweeter with waveguide
SB Acoustics SATORI AT60NC-4 Kapton AMT Tweeter
Audiotechnology C-Quenze 18 I 52 with LR magnet