What They Have in Common
Both land at essentially the same price, both offer 6x magnification, both hit ±1 yard accuracy, both include slope with a tournament-legal switch, and both have magnetic mounting. The baseline is identical — you're not choosing between a rangefinder and a toy here. This is a genuine features tradeoff between two solid options at the same price point.
Where They Differ
Display
This is probably the most meaningful difference for everyday use. The Series 4 Ultra runs an OLED display with brightness control, while the A1-Slope has a standard LCD. OLED displays produce higher contrast and read better in low-light conditions — early morning rounds, overcast days, heavily shaded tee boxes. Nobody actually reads a rangefinder in full sunlight; they're reading it in the shadow of their hand, or under tree cover. OLED wins in those conditions. The LCD on the A1-Slope is perfectly functional and Bushnell has been making readable LCD rangefinders for a long time, but it's the less premium display tech of the two.
Battery and Recharging
The A1-Slope is USB-C rechargeable and rated for 50+ rounds on a charge — roughly 3,000 actuations. The Series 4 Ultra runs on three CR2 batteries, which you replace when they're dead. Here's the tradeoff: CR2s are available at any pharmacy or grocery store in the country, which matters if you're away for a golf trip and the batteries die at 7am on day two. The A1-Slope's USB-C system is more convenient day-to-day — just plug it in overnight — but if you forget to charge it and you're two hours from home, you're stuck. Neither approach is wrong; it's a lifestyle question about whether you're a "charge it Sunday night" person or a "always keep a spare CR2 in the bag" person.
Size and Water Resistance
The A1-Slope is the smaller unit: 3.75 × 1.42 × 2.36 inches at 5.1 oz. Blue Tees doesn't publish dimensions or weight for the Series 4 Ultra, which is a minor frustration. What we know is the A1-Slope was explicitly designed to be compact — Bushnell calls it their smallest ever — so if pocket-friendliness matters to you, it likely wins on form factor. On water resistance, the A1-Slope also edges ahead: IPX6 versus IP54 on the Series 4 Ultra. IPX6 means it can handle sustained, heavy jets of water; IP54 handles splashing from any direction. In practical terms, both survive a rain round. But if you're regularly playing in serious Pacific Northwest weather or tend to leave your rangefinder out on a wet cart, IPX6 is the more robust rating.
Auto-Depth Filter and Feature Set
The Series 4 Ultra includes an auto-depth filter, which helps the unit lock the correct flag in layered target situations — think a flag with a tree line or hazard behind it. That's a real-world benefit on courses where clean flag locks can be tricky. The A1-Slope doesn't list a comparable feature. Both have pulse vibration confirmation and slope switch.
Who Should Buy Which
Get the Blue Tees Series 4 Ultra if:
- You play a lot of early morning rounds or tree-lined courses where display readability in low light actually matters
- You want the auto-depth filter to help lock the right target when there's something behind the flag
- You're a "throw CR2s in the bag and forget about it" type — you'd rather replace batteries once a season than remember to charge
- You're the 14-handicap who gets annoyed when the rangefinder struggles to isolate the flag on a tucked pin
Get the Bushnell A1-Slope if:
- You play regularly in rain and want the stronger IPX6 water resistance — the type who tees off when the forecast says 60% and doesn't blink
- You want the smallest possible unit; you're carrying a Sunday bag or just hate bulk on the cart
- You're already a USB-C person — phone, earbuds, everything charges the same way — and you want the rangefinder on that same routine
- You want Bushnell's established brand behind the product if that matters for resale, warranty confidence, or general peace of mind
The Bottom Line
At $299 vs $299.99, the price is a non-factor. This comes down to OLED versus rechargeable. The Series 4 Ultra's OLED display and auto-depth filter make it the better performer in pure yardage-getting terms. The A1-Slope's USB-C charging, IPX6 rating, and compact size make it the better fit if portability and weather-proofing are your priorities. I'd give the edge to the Series 4 Ultra for most golfers — the display advantage and auto-depth filter are things you notice every round, while the recharging convenience of the A1-Slope is only a win if you actually remember to plug it in.
Get the Blue Tees Series 4 Ultra.
See Also