The best 4.5 mm hex bit depends on whether you need a single magnetic power bit, several matching bits, or a set that includes other metric sizes. The HARFINGTON 100 mm bits suit users who want extra reach and magnetic screw retention; TEKTON’s 9-piece set is better for buyers who need multiple sizes, including 4.5 mm. For socket-wrench use, the TEKTON long hex bit socket offers a different format for reaching recessed fasteners.
| Product | Best For | Format |
|---|---|---|
| HARFINGTON 3-Piece H4.5 | Multiple matching power bits | 100 mm magnetic bits |
| TEKTON 9-Piece Hex Bit Set | A range of metric sizes | 30 mm bits |
| HARFINGTON 5-Piece H4.5 | Keeping spares on hand | 100 mm magnetic bits |
| HARFINGTON Single H4.5 | Replacing one bit | 100 mm magnetic bit |
| TEKTON 4.5 mm Long Hex Bit Socket | Socket-wrench access | Long-reach bit socket |
HARFINGTON 3-Piece H4.5 Magnetic Bits
These 4.5 mm metric hex driver bits are 100 mm (4 inches) long and have 1/4-inch hex shanks. Each bit is made from heat-treated S2 steel, with a sandblasted surface and a stated hardness of HRC 59–61. The magnetic tip is designed to help hold a screw while positioning it, including in tight spaces.
Best for: Buyers who use the H4.5 size regularly and want multiple matching bits. The longer length can help with reach compared with short insert bits. Choose this if magnetic screw retention and a 1/4-inch hex shank fit your setup. Limitation: All three pieces are the same size, so this is not a multi-size set.
TEKTON 9-Piece Metric Hex Bit Set
This set includes nine metric sizes from 2 mm through 6 mm, including the 4.5 mm bit. Each bit is 30 mm long, which is longer than the 25 mm standard length cited in the product details. The bits use S2 steel with a zinc-phosphate coating intended to resist corrosion, and the set includes a bit rail.
Best for: Users who need a 4.5 mm hex bit but also work with several nearby metric sizes. It offers more size flexibility than a pack of H4.5-only bits. Limitation: At 30 mm, these bits are shorter than the 100 mm HARFINGTON options, so they may not suit jobs requiring extra reach.
HARFINGTON 5-Piece H4.5 Magnetic Bits
This five-piece pack uses the same listed specifications as the HARFINGTON 3-piece version: 4.5 mm metric heads, 1/4-inch hex shanks, and 100 mm overall length. The S2 steel bits have heat-treated construction, a sandblasted surface, and magnetic tips. The product states a hardness range of HRC 59–61.
Best for: Buyers who want several identical bits available for regular work or replacements. It is better suited to stocking spares than building a range of hex sizes. Limitation: The pack contains only 4.5 mm bits, and the extra quantity is unnecessary if you need just one.
HARFINGTON Single H4.5 Magnetic Bit
This single 100 mm bit has a 4.5 mm hex head and a 1/4-inch hex shank. Its heat-treated S2 steel construction, sandblasted surface, and magnetic tip match the listed features of the multi-piece HARFINGTON options. The manufacturer describes the CNC-machined head as designed to reduce wear during high-intensity tightening.
Best for: Someone replacing a lost or worn H4.5 bit, or trying this long magnetic format without choosing a multipack. Limitation: One bit provides no spares, and its long body may be less convenient than a shorter bit where extra reach is not needed.
TEKTON 4.5 mm Long Hex Bit Socket
This TEKTON option is a 1/4-inch-drive, 4.5 mm long hex bit socket rather than a standalone 1/4-inch hex-shank power bit. Its long bit is described as providing 2.4 inches more reach than the brand’s standard-length bit sockets. Chamfered edges and a smooth top face are designed to support fastener engagement, while the bit is permanently pressed into the socket.
Best for: Buyers who want a socket-format tool for narrow or recessed areas. Choose it if your intended tool accepts the listed 1/4-inch drive. Limitation: The supplied features do not specify the socket’s overall length or a power-driver shank, so check the format you need before selecting it.
Buying Guide: Choosing a 4.5 mm Hex Bit
Do you need a driver bit or a bit socket?
A driver bit has a shank that fits a compatible driver or chuck; the HARFINGTON products specify a 1/4-inch hex shank. A bit socket is a separate format intended for a compatible socket drive. Match the connection to your tool before buying. The 4.5 mm measurement refers to the hex head size, not the shank or drive size.
Is one bit enough, or should you get a set?
Choose a single H4.5 bit when you need a replacement or use only that fastener size. A multipack of identical bits is more appropriate when you want spares. If you work with multiple metric fasteners, the TEKTON 9-piece set includes 4.5 mm alongside eight other sizes.
How much reach do you need?
The 100 mm HARFINGTON bits are the longest specified standalone power bits in this selection. TEKTON’s 30 mm set bits are shorter, while its long bit socket is described by comparison with its standard socket but has no overall length listed here. Consider the fastener’s location and the tool’s clearance before choosing.
Does magnetic retention matter?
The HARFINGTON bits are described as magnetic and intended to help hold screws during positioning. The TEKTON set and bit socket features provided here do not specify magnetic tips. If holding a screw on the bit is important, compare the stated feature rather than assuming all hex bits are magnetic.
Frequently Asked Questions
What does H4.5 mean on a hex bit?
H4.5 identifies a 4.5 mm hex head size. It does not describe the shank connection or the overall length.
Does the TEKTON 9-piece set include a 4.5 mm bit?
Yes. Its listed sizes include 4.5 mm, along with eight other metric sizes from 2 mm to 6 mm.
Are the HARFINGTON bits suitable for a 1/4-inch hex holder?
The product details specify a 1/4-inch hex shank. Confirm that your holder accepts that shank format.
Which option is intended for recessed fasteners?
The TEKTON long bit socket is specifically described as providing extra reach for deep, narrow, recessed areas. The 100 mm HARFINGTON bits also offer a longer overall length than the 30 mm TEKTON set bits.