Empress Effects – is an American boutique pedals maker founded in 2005. The key feature of the pedals by Empress Effects is that they are highly flexible and provide all possible tweaking of settings characteristic of a given effect.

Empress Effects: empresseffects.com

There are about 20 items in Empress Effects catalogue. I would point out these 4 as the most interesting for Ambient musicians. 

• Echosystem - ultimate delay-crafting tool. The pedal has 12 algorithm types, all with multiple variations giving you 36+ studio quality algorithms. Dual Delay Engines - 2 delays can be used at the same time, each with its own full set of controls and routed in serial, parallel or left/right. Settings can be saved to 35 presets. 3 variations of Cabinet Simulator. Hum-free operation when operating in stereo with two amps. 48kHz sampling, with 24 bit conversion and 32 bit internal processing.
• Reverb - Realistic simulations of spaces, as well as never-before-heard surreal ambiances are represented with stunning sound quality. The pedal has 12 algorithm types, some include multiple variations giving you 24 studio quality algorithms and counting. Ambient Sounds - A complete palette of tweak-able ambient sounds that offer the creative player so much territory to explore and make their own. Settings can be saved to 35 presets. 3 variations of Cabinet Simulator. Hum-free operation when operating in stereo with two amps. 48kHz sampling, with 24 bit conversion and 32 bit internal processing.
• Nebulus - brings guitarists high quality chorus, flanger and vibrato effects in a really compact 4.5 by 3.5 inch pedal. To increase the tone range even further 3 variations on each effect are available for a total of 9 tweak-able modes. Chorus - a lush and warm sounding chorus, a fluid and dreamy multi-chorus, and a unique tremolo'ed chorus. Flanger - a classic tape flange, a 70's negative feedback type flanger, and the elusive thru-zero flange. Vibrato - a standard vibrato, a classic vibe sound, and a rotating speaker effect.
• Multidrive - allows you to blend Overdrive, Distortion and Fuzz together, creating a full and rich array of tones that would not be available otherwise. All Analog Signal Path, independent control over the amount of fuzz, distortion and overdrive.