New Casio Edifice stainless-steel solar chronographs with sapphire crystal now available to buy

Sapphire crystal and 10-bar water resistance at ¥33,000 — about $208 — is the bit that makes the Casio Edifice EFS-S660 stand out. Most solar chronographs in that bracket (even from brands like Seiko) use mineral glass and stop at 50 meters. Casio's two new references, the steel EFS-S660D-1AJF and resin-strapped EFS-S660PB-1AJF do neither, and as of August 7, both can be bought outright on Casio Japan's store rather than reserved.

The EFS-S660D-1AJF features a polished stainless steel case with an integrated bracelet and one-touch three-fold clasp, a blue chronograph seconds hand, and 129 grams on the wrist. The EFS-S660PB-1AJF drops to 71 grams by swapping to a black resin band, and pairs a gray ion-plated case and black IP bezel with red chronograph hands. That one also carries Toyota Racing co-branding drawn from Casio's FIA World Endurance Championship partnership, which is a first for an entry-level Edifice.

Everything else is shared between the two models, as covered in our launch piece. Both sit in a 45.3 × 38.3 × 11.6 mm case, keep width under 39 mm, and that's the main reason why the series is "wearable." The sapphire crystal has an internal anti-reflective coating as well. The chronograph measures to 1/20 second across 60 minutes with split timing, and a tachymeter runs the dial periphery for average-speed calculation.

Casio needed a finish with visual depth that still passes enough light through to the solar cell underneath, which constrains how dark or dense the treatment can be. That's why the company went for a textured dial.

Casio has confirmed international availability for neither reference. Third-party Japanese retailers are also listing both, in some cases still as preorders with fulfillment tied to their own stock arrivals rather than Casio's release date.

Meanwhile you can also check out the Casio Edifice EF-527D-1AVEF on Amazon.