The Quick Verdict
Get the Blue Tees Series 4 Ultra. The OLED display with brightness control is a meaningful real-world upgrade over the CSi Pro's LCD, and at $299 vs $199.99, you're paying $99 for a noticeably better experience on the course — not just a shinier spec sheet. The CSi Pro is worth considering if the hundred dollars genuinely stings and you're comfortable with a more basic display. Check price at PlayBetter →
What They Have in Common
Both are 6x magnification rangefinders with ±1 yard accuracy, slope mode, and a slope switch for tournament play. They'll both lock onto a flag, vibrate to confirm, and give you a usable yardage. If you stripped out every differentiating feature, you'd have two rangefinders that do the core job at the same level.
Where They Differ
Display and Optics
Here's the thing: you read a rangefinder in the shade of your palm, squinting into a small eyepiece on a bright afternoon. An OLED display with adjustable brightness is not a minor perk — it's the thing you interact with on every single shot. The Series 4 Ultra's OLED renders numbers with better contrast and pop than a standard LCD, and the brightness control means you can dial it in whether you're playing at noon in July or in flat morning light. The CSi Pro's LCD gets the job done, but it's the kind of display you stop noticing when it works and notice immediately when it doesn't. Callaway does list multi-coated optics, which is a real differentiator for lens clarity, but no brightness control on the LCD side.
Range and Flag Lock
The Series 4 Ultra reaches 1,200 yards with flag lock out to 350 yards. The CSi Pro tops out at 1,000 yards with Callaway's Pin Acquisition Technology. For golf purposes, neither of these is a practical limitation — you're almost never ranging something beyond 450 yards. Flag lock performance at distance is where it matters, and the Series 4 Ultra's 350-yard flag lock ceiling is a genuine edge for those long par-3s and approach shots where you're trying to isolate the pin from the backdrop.
The CSi Pro's Club Selection Feature
The CSi Pro has something the Series 4 Ultra doesn't: a club selection mode that suggests which club to hit based on the adjusted yardage. It's called CSi (Club Selection Intelligence), and honestly, it's the most interesting thing about this rangefinder. Whether you find it useful or gimmicky probably depends on how far along your game is — a newer golfer might lean on it, while someone who already knows their distances well might toggle it off and forget about it. Either way, it's a feature you're not getting on the Blue Tees side.
Water Resistance and Build
The Series 4 Ultra is rated IP54, which means it's tested and certified against dust and splash. The CSi Pro is listed as "water-resistant" without a published IP rating — which is a step below. It'll survive a light drizzle, but IP54 is a more specific and defensible claim. If you play through early morning dew or the occasional surprise rain, the Blue Tees spec gives you more confidence. CR2 batteries on the Series 4 Ultra are worth mentioning: they're at every pharmacy in the country, which matters more than you'd think when you're scrambling before a round.
Who Should Buy Which
Get the Blue Tees Series 4 Ultra if:
- You play in variable light conditions — early tee times, late afternoons, or courses with a lot of tree cover where display brightness actually matters
- You're the golfer who's had a rangefinder let you down mid-round because the display washed out in direct sun
- You want a certified IP54 water resistance rating you can actually point to, not a general "water-resistant" label
- You're playing courses with long par-3s or blind approaches where the extra flag lock range and 1,200-yard ceiling give you something to work with
Get the Callaway CSi Pro if:
- You're rebuilding your bag budget after a putter fitting went longer than expected and $99 is genuinely the difference
- You're newer to the game and would actually use the club selection feature as a learning tool while you're still locking in your distances
- You want a known brand name on your rangefinder and the Callaway logo matters to your golf identity
- You want a lightweight, compact rangefinder (5.6 oz, pocketable dimensions) and size and weight are your deciding factors
The Bottom Line
The CSi Pro is a competent rangefinder at a fair price. But the Series 4 Ultra's OLED display with brightness control is a daily-use advantage that's hard to argue away. You'll use the display on every shot. Paying $99 more for a meaningfully better version of the thing you interact with most makes sense here. The club selection feature on the CSi Pro is interesting, but it's not the reason to buy a rangefinder. The display is.