Seymour Duncan Five-Two for Tele, STL52 and STR52

From the manufacturer:

application

Extremely balanced true single-coil Telecaster pickup developed for Nashville studio players. Recommended for traditional country, country pop, blues, and classic rock.

description
Tele® players often complain that their low strings sound "mushy" and their high strings are too bright - especially in the bridge position. The Five-Two concept corrects this with Alnico 5 magnets on the three low strings and Alnico 2 magnets on the three high strings. The result is an all-around, extremely well-balanced pickup with traditional output and vintage appointments such as vulcanized fibre bobbins, formvar wire, vintage magnet stagger and waxed cloth hookup cable. Rhythm model comes with chrome plated brass cover.

complete setup
Available for both rhythm and lead positions. Rhythm is RW/RP for hum canceling when using both pickups together.

guitars
For all well-balanced instruments. Works equally well with maple and rosewood fingerboards.

players
Brent Mason, Paul Martin / Oak Ridge Boys, Dean Parks, Michael Fath 

Best videos/sound-clips:

The Seymour Duncan SSL-52 pickups are equipped with both Alnico II and IV magnets, giving you the best of both worlds for so many sonic possibilities. This video takes you through the pickup in all three positions, highlighting its amazing balance and blend of tones. On the higher three strings, you'll notice a dampened treble attack that lends to smoother sounding highs with a lot of warmth. The lower three strings have a sweet presence that allows for a crisp and articulate sound (without losing the body of the low end). This design is great for players who complain about harsh sounding single coils in the higher ranges and muddiness in the low notes. The result is a very balanced and versatile pickup set that sounds pretty killer!

The player is Ron Shalita and he is using a 1983 Fender Telecaster through a 1954 Fender Super Amp and a Digital delay. He also uses a Wampler Hot Wired for dirt tones.

This video demos a Dr. Z amp using a Seymour Duncan SSL-52 in the bridge. This pup sounds great for that chicken pickin' country tone because it has a nice twang and bite, yet the tone remains really balanced and even in dynamics for a nice percussive feel. You'll notice that the highs never sound too bright and the lows never seem to muddy up, all thanks to the collaboration of Alnico II and IV magnets. Across all strings you will always have a balance in tone color and output, giving you a very rich and even sound.

The player is Brandon M. and he is using a Fender Telecaster through a Dr. Z Maz 38SR 212 amp.

Here is an extensive comparison of Squier Tele Affinity stock pickups vs. the Seymour Duncan Hot Tele (bridge) and SSL-52 (neck) pickups. The video goes through a number of clean and dirty tones with both the stock pickups and Seymour Duncans in all pickup positions. In regards to the SSL-52, you'll mainly notice that it is a bit darker sounding and has a slightly greater output than the stock pickup. The tonal variation mainly has to do with the Alnico IIs softening the treble response on high notes and the Alnico IVs boosting the low notes with punch and brilliance for a more even tone across all strings. The stock pickups sound much brighter and may have a little more clarity in this video. They also seem to have more of a tele 'twang' character, with a very snarly midrange and chimey top end. Depending on taste, both pickups have their own sonic personalities. I wouldn't necessarily say that the SSL-52 is an 'upgrade', but it definitely gives you a different voicing that could be advantageous for some applications.

The player is using a Squier Telecaster Affinity through a Marshall tube half stack  with an MXR Mm7 Custom Badass pedal (modified).