Brave Retro World explains:
Danelectro Spring King is a hybrid of real analog spring reverb and digital delay with a fixed delay time (about 66 milliseconds) and a lot of repeats.
- the library contains impulse responses in 24-bit mono wave audio (.wav) format for four sample rates;
- no sample rate conversion was used;
- available sample rates: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz;
- total 120+ impulse response for each of four sample rates;
- impulse response length is 4 seconds;
- includes Kick Pad noise samples.
Price: $12.99 at braveretroworld.com
A free demo with a limited set of impulse responses is available for download.