The JBL 18 inch Bass Naked Speaker, often referred to in its raw form as an 18″ subwoofer driver, is a high-performance component used in professional audio systems. Here are some general characteristics and features you might find in such a speaker:

1. Size: The speaker features an 18-inch cone, which allows it to produce deep, powerful bass frequencies.
2. Power Handling: JBL 18″ subwoofers are typically designed to handle high power levels, often ranging from 500 to 1600 watts RMS, with peak power handling capabilities significantly higher.
3. Frequency Response: These speakers are designed to reproduce low frequencies, typically from around 30 Hz to 3 kHz, making them ideal for enhancing bass in sound systems.
4. Sensitivity: JBL subwoofers usually have high sensitivity ratings, often around 96 dB or higher, which allows them to produce more sound output with less power.
5. Voice Coil: They often feature large, robust voice coils (4-inch diameter is common) that can handle high temperatures and provide reliable performance under heavy usage.
6. Magnet Structure: JBL uses high-quality magnets to ensure strong magnetic fields for precise and powerful bass reproduction.
7. Build Quality: The cone is typically made from durable materials such as paper or composite fibers, often reinforced with Kevlar or other strong materials. The frame is usually cast aluminum to provide strength without adding unnecessary weight.
8. Applications: These speakers are commonly used in professional audio setups including PA systems, concert sound systems, and high-end home theater systems, where powerful and clear bass is essential.

For the specific model, you would need to look up the exact specifications as JBL produces various 18″ subwoofer models with different characteristics tailored to different needs and applications.