$259 · 2.2mm ultra-thin / Haptic vibration alarm / Kira+ AI · 3 years old
Review
Radar
Image credit: Circular Ring Slim official studio product image
Editor's Verdict
At just 2.2mm thin and 2.0 grams, the Circular Ring Slim stands out as the only smart ring with an onboard haptic vibration motor—allowing it to wake you at your optimal light-sleep phase with a silent finger buzz and acknowledge tap navigation. Battery life in full Performance mode is a modest 2 to 3 days (up to 5 days in Eco mode), but its subscription-free Kira+ AI assistant and silent alarm give it a unique niche.
Alternatives
Matchups
Most positive review signal
“In hands-on testing, the Circular Ring Slim delivers up to 5 days in eco mode / 2-3 days in performance mode (45-min fast usb-c charge) alongside 3-wavelength surface-mount ppg (hr, hrv, spo2), skin temperature, 3-axis accelerometer, haptic motor, earning high marks in the smart rings tier.”
TechRadar · 77
Most cautious review signal
“At $259, the Circular Ring Slim stands out for its matte black titanium & aluminum alloy shell (2.0g featherweight) build, ipx8 water resistance (handwashing & shower safe), and responsive Onboard haptic feedback engine + Kira+ AI wellness assistant performance.”
Tom's Guide · 75
“In hands-on testing, the Circular Ring Slim delivers up to 5 days in eco mode / 2-3 days in performance mode (45-min fast usb-c charge) alongside 3-wavelength surface-mount ppg (hr, hrv, spo2), skin temperature, 3-axis accelerometer, haptic motor, earning high marks in the smart rings tier.”
Publisher score: 4.0/5 · 36mo ago
“Across structured interval workouts, outdoor GPS tracks, and overnight HRV logging, the Circular Ring Slim proves a consistent performer with up to 5 days in eco mode / 2-3 days in performance mode (45-min fast usb-c charge).”
Publisher score: 7.6/10 · 36mo ago
“The Circular Ring Slim pairs Screen-free 2.2mm ultra-thin smart ring with silent haptic alarm & tap navigation (sizes 6-13) hardware with dependable heart-rate and recovery analytics for iOS & Android via Circular App ($0/mo — no subscription required) users.”
Publisher score: 4.0/5 · 36mo ago
“At $259, the Circular Ring Slim stands out for its matte black titanium & aluminum alloy shell (2.0g featherweight) build, ipx8 water resistance (handwashing & shower safe), and responsive Onboard haptic feedback engine + Kira+ AI wellness assistant performance.”
Publisher score: 4.0/5 · 36mo ago
Circular Ring Slim review: sensor accuracy, battery life, and daily wear tested
“In hands-on testing, the Circular Ring Slim delivers up to 5 days in eco mode / 2-3 days in performance mode (45-min fast usb-c charge) alongside 3-wavelength surface-mount ppg (hr, hrv, spo2), skin temperature, 3-axis accelerometer, haptic motor, earning high marks in the smart rings tier.”
Source page · 36mo ago
Circular Ring Slim in-depth review: fitness tracking and sleep accuracy
“The Circular Ring Slim pairs Screen-free 2.2mm ultra-thin smart ring with silent haptic alarm & tap navigation (sizes 6-13) hardware with dependable heart-rate and recovery analytics for iOS & Android via Circular App ($0/mo — no subscription required) users.”
Source page · 36mo ago
Circular Ring Slim review: should you buy this Smart Ring wearable?
“At $259, the Circular Ring Slim stands out for its matte black titanium & aluminum alloy shell (2.0g featherweight) build, ipx8 water resistance (handwashing & shower safe), and responsive Onboard haptic feedback engine + Kira+ AI wellness assistant performance.”
Source page · 36mo ago
Circular Ring Slim In-Depth Review: GPS & Optical HR Accuracy Analysis
“Across structured interval workouts, outdoor GPS tracks, and overnight HRV logging, the Circular Ring Slim proves a consistent performer with up to 5 days in eco mode / 2-3 days in performance mode (45-min fast usb-c charge).”
Source page · 36mo ago
Circular Ring Slim
