We literally started with a blank sheet of paper and engineered everything to offer the best possible reliability and performance. Many prototypes, re-designs and modifications were made and a tremendous amount of reliability testing was undertaken in order to ensure outstanding longevity. Using custom designed coils and spiders tuned to each exact model we were able to develop for excellent excursion and power handling while implementing measures to prevent coil rub. The motor venting has been carefully designed to offer a good balance between noise reduction and cooling efficiency. The build of the woofer also incorporates some measures to add additional durability for extreme use. The high roll surround was chosen to allow to peak excursion while maintaining good cone area. In normal use the surround will not be put to its maximum limits - this helps to improve longevity. The added bead of glue above and below the coil helps to prevent separation of the coil when used in extreme situations. Oversized 4 AWG terminals make for easy installation and allow easy use of multiple cables to the one terminal when running multiple woofer configurations. Safe for use in almost any enclosure - bandpass, vented or sealed. Not for use in free air/infinite baffle configuration. For keen enthusiasts this woofer offers good musicality whilst maintaining great power handling and surprisingly good deep bass performance. Indy S is the Swiss Army Knife subwoofer. We also offer recone kits for competition use.