The D75/25 should have both side and top posts.
The D35 is the same size but has top posts only.

 

Bunger, did you have to change over to a stronger alternator with the twin batteries?

 

No, but I installed an IBS dual battery monitoring unit.
There are a few other systems out there but IBS and National Luna are the most common.
They basically make sure the secondary battery is always fully charged and allow you to jumpstart yourself wth a push of a button if the primary battery dies.

 

After looking around at several options oddysey optima ect. I went with the red top that optima recommended on their site for the '07 H3 (no trimming or issues with the box or cover at all? Perfect fit had to remove the factory red and black cheap plastic terminal covers though and twist the factory tie down strap once or twice as the optima is slightly shorter) And also had to spread "a fair bit" the factory terminals apart to get them to seat down low enough to grab well, as the optima has larger diameter top posts then the delco. They kept popping off once or twice while tightening down the terminal clamp lesson learned. 1 year and the only problem was 'my own stupidity' of leaving the lights on before a third day concert came out to a dead battery oops. Quik jump from a parking attendant thankfully right there and all is well. The main reason for optima over oddysey (not common in my area) was replacement if ever needed was really going to be a hassle but optima's are regular stock item at one of my local parts store chain. 3+ year free replacement.
For reference the model was Red Top part # 8025-160
Optima 8025-160 Technical Details

12-Volt, 720 Cold Cranking Amps, Size: 10 5/16″ x 6 13/16″ x 7 5/8″ tall, Weight: 39.5 pounds, SAE Posts

List price was $458.81 scary
I paid 188.33
Odd I just searched the optima web site and now the '07 H3 listing for applications is gone?... oh well, I can assure anyone that model I listed is 100% correct for 2007 H3 and easy install no trimming needed. Highly reccomend Optima even though there are numerous bad rap postings all over the web. I think a lot of that has to do with people choosing the wrong one in the first place. Like a yellow top to compliment their winch that never gets used. Only buy a deep cycle if you plan on using it for it's intended purpose OR I actually hear people saying I want one that matches the color of my car. If that is the case please paint your car/jeep suv or whatever to match the correct optima you should buy for your vehicle or application. I'm sorry for all the OPTIMA bashers around All I have is a two thumbs up positive review here

 

bowtieturninghummerguy? -
You may also consider changing out those stock battery terminals.
You might have noticed that they don't grab much of the top post and are serrated on the inside, which allows corrosion to develop. I had problems with mine and changed them out to military style posts and have had no problems since.
That may be one reason why I trimmed my battery cover, to accommodate those new posts
You probably have read on this forum how the stock posts have been a concern for some time.
Glad you are up and running with your new battery

 

Thanks yes, these are the ones I chose to use, small but heavy. High quality platinum coating. Had them laser etched by a local shop with positive + and negative - clearly marked just in case someone other than me JUMPS my ride !!!
These ones fit well without any trimming needed and have really nice cheap plastic clear covers to replace the really nice cheap plastic red and black ones I chucked during the optima swap! I am not 100% sure these ones I chose would fit all the H3's though? If I recall somewhere in the memory bank, the gauge size, number of wires, wire routing for the battery cables is not all the same through the H3 years?