From the Dawner Prince website:

STARLA™ Tap Tempo Tremolo

We took a challenge and went a step further by designing  the most
compact size, top sounding, all-feature tap tempo tremolo effect pedal
nowadays! Starla is a synthesis of two precisely combined electronics.
It is a superb sound quality analog tremolo controlled by a versatile digital tap tempo microprocessor via optical technology – a light source and photocell.

FEATURES:

Depth
On minimum settings, Starla can be used as a
signal booster. Increasing the depth control, increases the tremolo
effect in your signal; from light shimmering, through mild
transparent-traditional, all the way to a deep swings and ‘machine
gun-like’ sounds. Thanks to a huge depth range, this tremolo is able to
chop up any signal sent in or out of it. It is very useful when put in
front of high gain amps or pedals as it can cut the sound down to a
dead silence.

Speed

There are 3 ways to set the speed of the tremolo effect: by using a
speed knob, tap tempo footswitch or control voltage/remote tap switch
via Sync port. Speed is affected by the position of the Multiplier
(1/3/2) toggle switch. If the Multiplier switch is set at a higher rate,
speed knobs sweep will change as well.

Waveform
Starla utilizes eight different
waveforms, including a random one. Combining every waveform with Duty
trim potentiometer produces numerous wave shapes for you to
explore. Duty trimmer pot modifies the duty cycle of all waveforms
except Random.

Volume
We added volume control for two reasons:
first to avoid a noticeable drop in volume when effect is engaged,
which is a problem most tremolos have, and second to be able to use
Starla as an excellent volume booster without adding any distortion to
the signal when Depth control is on minimum setting.

Sync port
This port allows Starla to communicate
with other devices. Depending on how the internal jumper is set up
(remove the backplate to reach the jumper), Starla can send control
signal to synchronize other devices to its’ LFO rate or it can accept
control signal to be synchronized by other devices. It can also accept
remote tap foot switch.

Tap tempo
Starla’s tap tempo microprocessor
calculates tempo by taking the last two user taps so it plays in sync
with your music. You can also choose different tap to tremolo rate
ratios using 1/3/2 Multiplier switch: 1:1, 1:2 and 1:3. Once a tempo
has been tapped in, Multiplier switch serves as an in-time speed
control.

True bypass
Starla Tap Tempo Tremolo is equipped
with microprocessor driven true bypass relay switching system. Holding
down Status footswitch during the power up allows you to preset whether
the effect powers up in effect-on or effect-bypass mode.

We are very proud of our Starla™ Tap Tempo Tremolo effect pedal and
we believe it will inspire you to be even more creative in making music!
Enjoy!

Technical Specifications:

Power Input Voltage:   9 - 12V

Power input connector: 2.1mm barrel connector (Negative tip)

Power Consumption:   ~ 35mA

Size:   4.4” x 2.3”