The Kastl Drum Pack is built up of four distinct electronic drum kits, using the Kastle Lo-Fi Modular Synth from Bastl’s distinct tone as the initial source, or oscillator, and full inspiration. The Kastle Kits in Ableton are highly modifiable, as the Envelopes and Filters existing within the Ableton Drum Racks and Simplers are greatly used to further sculpt the tones, feel and dynamics. Feel free to further sculpt the filter and envelope settings to create your own drums, basses, synths, or more.
If you have Ableton, open the included session and copy the Drum kits on display within the session in to your existing Ableton Library. Or, feel free to make kits of your own in any DAW with the included, itemized, individual samples rendered as audio files in any way that sounds good to your ears.
More about Bastl Kastl: http://www.bastl-instruments.com/instruments/kastle/
Bastl Kastl Review: https://ask.audio/articles/review-bastl-kastle-mini-modular-synth