Background and Purpose: The Tigertriever is a novel, radially adjustable, fully visible, stentriever that permits the operator to align radial expansion with target vessel diameters. This multicenter trial compared the Tigertriever's effectiveness and safety compared with established stent retrievers. Methods: Single arm, prospective, multicenter trial comparing the Tigertriever to efficacy and safety performance goals derived from outcomes in six recent pivotal studies evaluating the Solitaire and Trevo stent-retriever devices with a lead-in and a main-study phase. Patients were enrolled if they had acute ischemic stroke with NIHSS > /=8 due to large vessel occlusion within 8 hours of onset. The primary efficacy endpoint was successful reperfusion, defined as core laboratory-adjudicated modified Thrombolysis in Cerebral Ischemia (mTICI) score 2b-3 within three passes of the Tigertriever. The primary safety endpoint was a composite of 90-day all-cause mortality and symptomatic intracranial hemorrhage (sICH). Secondary efficacy endpoints included 3-month good clinical outcome (modified Rankin Scale 0-2) and first-pass successful reperfusion. Results: Between May 2018 and March 2020, 160 patients (43 lead-in, 117 main phase) at 17 centers were enrolled and treated with the Tigertriever. The primary efficacy endpoint was achieved in 84.6% in the main-study phase group compared with the 63.4% performance goal and the 73.4% historical rate (non-inferiority p < 0.0001; superiority p < 0.01). The first pass successful reperfusion rate was 57.8%. After all interventions, successful reperfusion (mTICI > /=2b) was achieved in 95.7% and excellent reperfusion (mTICI 2c-3) in 71.8%. The primary safety composite endpoint rate of mortality and sICH was 18.1% compared with the 30.4% performance goal and the 20.4% historical rate (non-inferiority p=0.004; superiority p=0.57). Good clinical outcome was achieved in 58% at 90 days. Conclusions: The Tigertriever device was shown to be highly effective and safe compared to Trevo and Solitaire devices to remove thrombus in large vessel occlusive stroke patients eligible for mechanical thrombectomy. Registration: URL: http://www.clinicaltrials.gov; Unique identifier: NCT03474549.