The ProMariner Gulfstream GS50 and Gulfstream GS30 are compact nearly identical 7 x 50 marine binoculars. We cover both on this page.
Both are fairly light, weighing in at a mere 35-ounces. The pair features a squat design and measure right at six inches high when standing on the front lens caps.
Both Gulfstream binoculars have individual eye focus with the diopter scale located on the topside of the eyepieces. This is not our preferred location for these indices.
Index marks were painted on the eyepieces of each binocular and on the GS30 one paint mark was smeared making it hard to use. Index marks were printed on the housing.
We noted the diopter adjustment on both sets were stiff enough to require two fingers to fine tune.
Both the GS30 and GS50 suffered from a significant reduction in the field of view when the user wore eyeglasses.
Optical acuity of this pair of ProMariner binos was good. We did however note some difficulty seeing the compass both with and without eyeglasses.
A magenta coating on the GS50 objective lens made images take on a cool, bluish appearance.
In my opinion, the case supplied with each binocular offered minimal protection against the elements.
The neck strap provided with each had a small neck pad, but offered no floatation.
Front lens caps were attached to the center hinge. The caps fit the lens tubes properly and were easy to put on and remove.
The left lens tube on the GS50 had a sliding scale distance calculator.
Mediocre ratings leave this pair stuck in the middle of the pack.